chore: re-add build files

.github/workflows/build.yml

@@ -0,0 +1,45 @@
+name: build
+
+on: [ workflow_dispatch ]
+
+jobs:
+  everything:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Cache Docker layers
+        uses: actions/cache@v4
+        with:
+          path: /tmp/.buildx-cache
+          key: ${{ runner.os }}-buildx-updatetar
+          restore-keys: |
+            ${{ runner.os }}-buildx-updatetar
+      - name: Build Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: build/ci.Dockerfile
+          load: true
+          tags: ci_image:latest
+          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-to: type=local,dest=/tmp/.buildx-cache-new
+
+      - name: Extract artifact from Docker image
+        run: |
+          docker create --name extract_artifact ci_image:latest
+          docker cp extract_artifact:/lamassu-server.tar.gz ./lamassu-server.tar.gz
+          docker rm extract_artifact
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: lamassu-server.tar.gz
+          path: lamassu-server.tar.gz
+
+      - name: Move cache
+        run: |
+          rm -rf /tmp/.buildx-cache 
+          mv /tmp/.buildx-cache-new /tmp/.buildx-cache