refactor: update build process to create a single all-in-one Docker image and adjust related configurations

.gitea/workflows/build.yml

@@ -1,4 +1,4 @@
-name: Build Production Images
+name: Build Production Image
 
 on:
   pull_request_review:
@@ -6,7 +6,7 @@ on:
 
 jobs:
   build:
-    name: Build Production Images
+    name: Build Production Image
     if: github.event.review.state == 'approved' && github.event.pull_request.base.ref == 'main'
     runs-on: ubuntu-latest
     steps:
@@ -18,8 +18,5 @@ jobs:
       - name: Verify Docker CLI
         run: docker version
 
-      - name: Build backend image
-        run: docker build -t condado-newsletter-backend:latest -f backend/Dockerfile ./backend
-
-      - name: Build frontend image
-        run: docker build -t condado-newsletter-frontend:latest -f frontend/Dockerfile ./frontend
+      - name: Build all-in-one image
+        run: docker build -t condado-newsletter:latest -f Dockerfile.allinone .