HOTFIX update nix versions in CI workflows (#4124)

The release workflow gets stuck on an invalid option when trying to
build and cache the released version. K Framework uses nix-2.30.1 in CI
so we pin to that one, too.

Also removing some old workflow files from when booster was a repo of
its own.

Author: jberthold

.github/workflows/release.yml

@@ -45,7 +45,7 @@ jobs:
       - name: Install Nix
         uses: cachix/install-nix-action@v25
         with:
-          install_url: https://releases.nixos.org/nix/nix-2.13.3/install
+          install_url: https://releases.nixos.org/nix/nix-2.30.1/install
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
             substituters = http://cache.nixos.org https://cache.iog.io

.github/workflows/test.yml

@@ -30,7 +30,7 @@ jobs:
       - name: 'Install Nix'
         uses: cachix/install-nix-action@v25
         with:
-          install_url: https://releases.nixos.org/nix/nix-2.13.3/install
+          install_url: https://releases.nixos.org/nix/nix-2.30.1/install
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
             substituters = http://cache.nixos.org https://cache.iog.io
@@ -99,7 +99,7 @@ jobs:
         if: ${{ !startsWith(matrix.os, 'self') }}
         uses: cachix/install-nix-action@v25
         with:
-          install_url: https://releases.nixos.org/nix/nix-2.13.3/install
+          install_url: https://releases.nixos.org/nix/nix-2.30.1/install
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
             substituters = http://cache.nixos.org https://cache.iog.io
@@ -133,7 +133,7 @@ jobs:
       - name: Install Nix
         uses: cachix/install-nix-action@v26
         with:
-          install_url: https://releases.nixos.org/nix/nix-2.13.3/install
+          install_url: https://releases.nixos.org/nix/nix-2.30.1/install
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
             substituters = http://cache.nixos.org https://cache.iog.io
@@ -248,7 +248,7 @@ jobs:
       - name: 'Install Nix'
         uses: cachix/install-nix-action@v25
         with:
-          install_url: https://releases.nixos.org/nix/nix-2.13.3/install
+          install_url: https://releases.nixos.org/nix/nix-2.30.1/install
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
             substituters = http://cache.nixos.org https://cache.iog.io

.github/workflows/update-deps.yml

@@ -27,7 +27,7 @@ jobs:
       - name: 'Install Nix/Cachix'
         uses: cachix/install-nix-action@v19
         with:
-          install_url: https://releases.nixos.org/nix/nix-2.13.3/install
+          install_url: https://releases.nixos.org/nix/nix-2.30.1/install
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
       - uses: cachix/cachix-action@v12