add gitea jobs and runner configuration

build and deploy colmena hive using gitea actions

.gitea/workflows/deploy.yaml

@@ -0,0 +1,22 @@
+on: [push]
+
+jobs:
+  deploy:
+    permissions:
+      contents: read
+      id-token: write
+    name: build hive configuration
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v4
+      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: DeterminateSystems/magic-nix-cache-action@main
+      - name: Install SSH key
+        uses: shimataro/ssh-key-action@v2
+        with:
+          key: ${{ secrets.SSH_KEY }}
+          known_hosts: ${{ secrets.KNOWN_HOSTS }}
+      - uses: http://github.com/cachix/cachix-action@v16
+        with:
+          name: colmena
+      - run: nix run .#colmena apply