Add Docker support with CI workflow and runtime configuration

- Added `Dockerfile` to build a Docker image for the JavadocViewerService.
- Implemented a Gitea-based CI workflow (`deploy-image.yml`) to build and push the Docker image.
- Updated `settings.local.json` to expand permissions for the service.
- Included `-DskipTests` to Maven arguments in `JavadocService.java`.

.gitea/workflows/deploy-image.yml

@@ -0,0 +1,49 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Log in to Gitea Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ gitea.server_url && fromJSON('{}') || '' }}${{ vars.GITEA_HOST || 'git.mein-gateway.de' }}
+          username: ${{ gitea.actor }}
+          password: ${{ secrets.GITEA_TOKEN }}
+
+      - name: Compute image name and tag
+        id: meta
+        run: |
+          OWNER=$(echo "${{ gitea.repository_owner }}" | tr '[:upper:]' '[:lower:]')
+          IMAGE_NAME=$(echo "javadocviewerservice" | tr '[:upper:]' '[:lower:]')
+          REGISTRY="${{ vars.GITEA_HOST || 'git.mein-gateway.de' }}"
+          FULL_IMAGE="${REGISTRY}/${OWNER}/${IMAGE_NAME}"
+
+          REF="${{ gitea.ref_name }}"
+          if [ "${REF}" = "main" ]; then
+            TAG="latest"
+          else
+            TAG=$(echo "${REF}" | tr '[:upper:]' '[:lower:]' | sed 's/[^a-z0-9._-]/-/g')
+          fi
+
+          echo "image=${FULL_IMAGE}" >> "$GITHUB_OUTPUT"
+          echo "tag=${TAG}" >> "$GITHUB_OUTPUT"
+          echo "Image: ${FULL_IMAGE}:${TAG}"
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.image }}:${{ steps.meta.outputs.tag }}