Migrate from polyrepo to monorepo (#17)

## **Description**

This PR migrates the current MetaMask design system repo which is
currently using the metamask-module-template and a polyrepo structure to
a monorepo structure. The primary goal is to streamline the module
management process by consolidating multiple repositories into a single
monorepo. The `core` module serves as a reference for the files and
structure required in the monorepo setup. This change will simplify
dependency management and improve development efficiency across modules.

<img width="444" alt="Screenshot 2024-10-08 at 2 09 12 PM"
src="https://github.com/user-attachments/assets/eb1dcb2e-4eb1-45bb-833f-4fbe3295c84f">

### Key changes:
- Updated module configuration to align with the monorepo structure.
- Consolidated files and dependencies into the monorepo format.
- Ensured consistency with the `core` module in terms of file inclusion,
structure, and build processes.

## **Related issues**

Fixes: #5

## **Manual testing steps**

1. Clone the repository and navigate to the monorepo.
2. Run all `yarn` scripts to ensure they work with the exception of
`prepare-preview-build` and `publish-previews`
3. Verify that the scriptsfunction as expected within the monorepo.
4. Ensure the build passes without issues in the monorepo format.
5. Ensure no instances of "core" remain unless links to information for
migrating packages

## **Screenshots/Recordings**

Video showing all `yarn` scripts work from `package.json` with the
exception of `prepare-preview-build` and `publish-previews` issue here:
#26

https://www.loom.com/share/4f40fa33ae45472e807137d3995c212c

## **Pre-merge author checklist**

- [x] I’ve followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs)
- [x] I’ve completed the PR template to the best of my ability
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and/or screenshots.

.depcheckrc.yml

@@ -0,0 +1,25 @@
+---
+ignores:
+  # Ignore dependencies used by Yarn binaries in `.yarn`
+  - '@yarnpkg/*'
+  - 'clipanion'
+  - 'typanion'
+  # Ignore dependencies imported implicitly by TypeScript
+  - '@types/*'
+  # Ignore tools (packages which we use as executables and not libraries)
+  - '@lavamoat/allow-scripts'
+  - '@metamask/auto-changelog'
+  - '@metamask/create-release-branch'
+  - 'depcheck'
+  - 'eslint-interactive'
+  - 'rimraf'
+  - 'simple-git-hooks'
+  - 'ts-node'
+  - 'typedoc'
+  # Ignore plugins implicitly imported by tools
+  - 'jest-silent-reporter'
+  - 'prettier-plugin-packagejson'
+  # Ignore plugins we explicitly use with tools
+  - 'babel-jest'
+  # Ignore dependencies which plug into the NPM lifecycle
+  - '@lavamoat/preinstall-always-fail'

.editorconfig

@@ -1,9 +1,13 @@
+# http://editorconfig.org
 root = true
 
 [*]
-indent_style = space
-indent_size = 2
-end_of_line = lf
 charset = utf-8
-trim_trailing_whitespace = true
+end_of_line = lf
+indent_size = 2
+indent_style = space
 insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false

.eslintrc.js

@@ -1,50 +1,76 @@
 module.exports = {
   root: true,
-
-  extends: ['@metamask/eslint-config'],
-
+  extends: ['@metamask/eslint-config', '@metamask/eslint-config-nodejs'],
+  ignorePatterns: [
+    '!.eslintrc.js',
+    '!jest.config.js',
+    'node_modules',
+    '**/dist',
+    '**/docs',
+    '**/coverage',
+    'merged-packages',
+    'scripts/create-package/package-template',
+  ],
   overrides: [
     {
-      files: ['*.ts'],
-      extends: ['@metamask/eslint-config-typescript'],
+      files: ['*.test.{ts,js}'],
+      extends: ['@metamask/eslint-config-jest'],
     },
-
     {
-      files: ['*.js'],
+      files: ['*.js', '*.cjs'],
       parserOptions: {
         sourceType: 'script',
+        ecmaVersion: '2020',
       },
-      extends: ['@metamask/eslint-config-nodejs'],
     },
-
     {
-      files: ['yarn.config.cjs'],
+      files: ['*.ts'],
+      extends: ['@metamask/eslint-config-typescript'],
       parserOptions: {
-        sourceType: 'script',
-        ecmaVersion: 2020,
+        tsconfigRootDir: __dirname,
+        project: ['./tsconfig.packages.json'],
       },
-      settings: {
-        jsdoc: {
-          mode: 'typescript',
-        },
+      rules: {
+        '@typescript-eslint/no-explicit-any': 'error',
       },
-      extends: ['@metamask/eslint-config-nodejs'],
     },
-
     {
-      files: ['*.test.ts', '*.test.js'],
-      extends: [
-        '@metamask/eslint-config-jest',
-        '@metamask/eslint-config-nodejs',
-      ],
+      files: ['*.d.ts'],
+      rules: {
+        '@typescript-eslint/naming-convention': 'warn',
+        'import/unambiguous': 'off',
+      },
+    },
+    {
+      files: ['scripts/**/*.ts'],
+      rules: {
+        'import/no-unassigned-import': 'off',
+        'n/no-sync': 'off',
+        // All scripts will have shebangs.
+        'n/shebang': 'off',
+      },
     },
   ],
-
-  ignorePatterns: [
-    '!.eslintrc.js',
-    '!.prettierrc.js',
-    'dist/',
-    'docs/',
-    '.yarn/',
-  ],
+  rules: {
+    camelcase: 'off',
+    'id-length': 'off',
+    'no-restricted-syntax': [
+      'error',
+      'ForInStatement',
+      'LabeledStatement',
+      'WithStatement',
+    ],
+    'jsdoc/match-description': [
+      'off',
+      { matchDescription: '^[A-Z`\\d_][\\s\\S]*[.?!`>)}]$' },
+    ],
+  },
+  settings: {
+    'import/resolver': {
+      typescript: {},
+    },
+    jsdoc: {
+      mode: 'typescript',
+    },
+  },
 };

.github/dependabot.yml

@@ -7,9 +7,6 @@ updates:
     directory: '/'
     schedule:
       interval: 'daily'
-      time: '06:00'
     allow:
       - dependency-name: '@metamask/*'
-    target-branch: 'main'
-    versioning-strategy: 'increase-if-necessary'
-    open-pull-requests-limit: 10
+    versioning-strategy: 'increase'

.github/workflows/ensure-blocking-pr-labels-absent.yml

@@ -0,0 +1,37 @@
+name: 'Check for PR labels that block merging'
+on:
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - labeled
+      - unlabeled
+
+jobs:
+  ensure-blocking-pr-labels-absent:
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: read
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: '.nvmrc'
+      - name: Install Yarn
+        run: corepack enable
+      - name: Restore Yarn cache
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: '.nvmrc'
+          cache: 'yarn'
+      - run: yarn --immutable
+      - name: Run command
+        uses: actions/github-script@v7
+        with:
+          script: |
+            if (context.payload.pull_request.labels.some((label) => label.name === 'DO-NOT-MERGE')) {
+              core.setFailed(
+                "PR cannot be merged because it contains the label 'DO-NOT-MERGE'."
+              );
+            }