[ci] add attestations to Docker image

With this PR merged all Docker images built in CI will have SBOM and provenance.
This will check two additional policy boxes in Docker Scout.

The quiet flag from maven was removed again in order to be able to verify the docker build.

Author: line-o

.github/workflows/ci-container.yml

@@ -37,8 +37,16 @@ jobs:
         uses: docker/setup-qemu-action@06116385d9baf250c9f4dcb4858b16962ea869c3  # v4
         with:
           platforms: linux/amd64,linux/arm64
+      - name: Enable containerd image store
+        run: |
+          echo '{ "features": { "containerd-snapshotter": true } }' | sudo tee /etc/docker/daemon.json
+          sudo systemctl restart docker
+      - name: Verify containerd snapshotter is active
+        run: docker info -f '{{.DriverStatus}}'
       - name: Make buildkit default
         uses: docker/setup-buildx-action@d7f5e7f509e45cec5c76c4d5afdd7de93d0b3df5  # v4
+        with:
+          driver: docker
         id: buildx
       - uses: ./.github/actions/maven-cache
       - uses: ./.github/actions/maven-github-settings
@@ -60,7 +68,8 @@ jobs:
             VERSION="${{ github.ref_name }}"
             REVISION_ARG="-Drevision=${VERSION#eXist-}"
           fi
-          mvn -V -B --no-transfer-progress -q \
+          mvn -V -B --no-transfer-progress \
+            -Ddocker.sbom=true -Ddocker.provenance=true \
             -Pdocker,skip-build-dist-archives \
             -DskipTests -Ddependency-check.skip=true \
             $REVISION_ARG \