Add Code-Quality CI template

lib/gitlab/ci/templates/Code-Quality.gitlab-ci.yml

+code_quality:
+  image: docker:stable
+  allow_failure: true
+  # gitlab-org runners set `privileged: false` but we need to have it set to true
+  # since we're using Docker in Docker
+  tags: []
+  before_script: []
+  services:
+    - docker:stable-dind
+  variables:
+    SETUP_DB: "false"
+    DOCKER_DRIVER: overlay2
+  cache: {}
+  dependencies: []
+  script:
+    # Extract "MAJOR.MINOR" from CI_SERVER_VERSION and generate "MAJOR-MINOR-stable" for Security Products
+    - export SP_VERSION=$(echo "$CI_SERVER_VERSION" | sed 's/^\([0-9]*\)\.\([0-9]*\).*/\1-\2-stable/')
+    - docker run
+        --env SOURCE_CODE="$PWD"
+        --volume "$PWD":/code
+        --volume /var/run/docker.sock:/var/run/docker.sock
+        "registry.gitlab.com/gitlab-org/security-products/codequality:$SP_VERSION" /code
+  artifacts:
+    reports:
+      codequality: gl-code-quality-report.json
+    expire_in: 1 week