ci(GitLab): Add integration test target for containerized tests

Signed-off-by: David Runge <dvzrv@archlinux.org>

.gitlab-ci.yml

@@ -104,6 +104,17 @@ integration-test:
   tags:
     - vm
 
+containerized-integration-test:
+  extends: .default
+  script:
+    - useradd -m testuser
+    - loginctl enable-linger testuser
+    - chown -R testuser:testuser .
+    - WORKDIR="$(pwd)" runuser -w WORKDIR -l testuser -c 'env && cd "$WORKDIR" && just install-rust-dev-tools && just build-container-integration-test-image && just containerized-integration-tests'
+  stage: test
+  tags:
+    - vm
+
 test-readmes:
   extends: .default
   script: