GitHub app import+export and links (windmill-labs#870)

* github app for git sync

* Link + features list

* updating screenshot

* udpdated images

* export import docs

* add some links

---------

Co-authored-by: Henri Courdent <[email protected]>
Co-authored-by: hcourdent <[email protected]>
Co-authored-by: Alex <[email protected]>

Author: 3 people

docs/advanced/11_git_sync/index.mdx

@@ -204,4 +204,9 @@ More details at:
 		description="Develop locally, push to git and deploy automatically to Windmill."
 		href="/docs/advanced/local_development"
 	/>
+	<DocCard
+		title="GitHub App"
+		description="Install the Windmill GitHub app to simplify setting up Git sync"
+		href="/docs/integrations/git_repository#github-app"
+	/>
 </div>

docs/advanced/9_deploy_gh_gl/index.mdx

@@ -116,7 +116,7 @@ For instance, a [resource](../../core_concepts/3_resources_and_types/index.mdx)
 ### Setup git sync
 
 1. In Windmill, navigate to the workspace settings and go to the [Git sync](../11_git_sync/index.mdx) tab.
-2. Create a `git_repository` [resource](../../core_concepts/3_resources_and_types/index.mdx) with the necessary URL, username, repo name, and a GitHub token.
+2. Create a `git_repository` [resource](../../core_concepts/3_resources_and_types/index.mdx) with the necessary URL, username, repo name, and a GitHub token. You can also use a [GitHub app installation](../integrations/git_repository#github-app) to connect a repo to your windmill instance.
 3. Generate a fine-grained GitHub [token](https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/managing-your-personal-access-tokens#creating-a-fine-grained-personal-access-token) with read and write permissions for content and add it to the Windmill `git_repository` resource.
 
 Your URL should be `https://[USERNAME]:[TOKEN]@github.com/[ORG|USER]/[REPO_NAME].git`

docs/integrations/git_repository.mdx

@@ -40,4 +40,12 @@ As a [Windmill workspace admin](https://www.windmill.dev/docs/core_concepts/role
 
 :::warning
 You will only be able to use the installation token for [Git sync](../advanced/11_git_sync/index.mdx).
-:::
+:::
+
+### Importing / Exporting to/from other windmill instance
+
+A GitHub app can only be installed to a GitHub organization once. Hence to associate an installation to multiple windmill instances you need to export the associated JWT token on the source instance using the "Export" button and paste the JWT in the destination instance to import the installation.
+
+:::warning
+The JWT token associated to your GitHub app installation is sensitive and has the rights to request a short lived installation token. To revoke the JWT, you need to uninstall the GitHub app from your organization and re-install it to re-associate it with a windmill instance.
+:::