Also push image to ghcr.io/gameyfin/app

Use caching in Docker build
Improve error handling

.github/actions/docker-build-push/action.yml

@@ -0,0 +1,57 @@
+name: 'Docker Build and Push'
+description: 'Builds and pushes Docker images to Docker Hub and GHCR with flexible tagging.'
+runs:
+  using: 'composite'
+  steps:
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+
+    - name: Log in to Docker Hub
+      uses: docker/login-action@v3
+      with:
+        username: ${{ inputs.dockerhub_username }}
+        password: ${{ inputs.dockerhub_token }}
+
+    - name: Log in to GitHub Container Registry
+      uses: docker/login-action@v3
+      with:
+        registry: ghcr.io
+        username: ${{ inputs.ghcr_username }}
+        password: ${{ inputs.ghcr_token }}
+
+    - name: Build and push Docker image
+      uses: docker/build-push-action@v5
+      with:
+        context: ${{ inputs.context }}
+        file: ${{ inputs.dockerfile }}
+        platforms: ${{ inputs.platforms }}
+        push: true
+        tags: ${{ inputs.tags }}
+        cache-from: type=gha
+        cache-to: type=gha
+
+inputs:
+  dockerhub_username:
+    required: true
+    description: 'Docker Hub username'
+  dockerhub_token:
+    required: true
+    description: 'Docker Hub token'
+  ghcr_username:
+    required: true
+    description: 'GHCR username'
+  ghcr_token:
+    required: true
+    description: 'GHCR token'
+  context:
+    required: true
+    description: 'Build context'
+  dockerfile:
+    required: true
+    description: 'Dockerfile path'
+  platforms:
+    required: true
+    description: 'Platforms to build for'
+  tags:
+    required: true
+    description: 'Comma-separated list of image tags'