Add gitlab CI config

.ansible-lint

+skip_list:
+  - role-name

.gitlab-ci.yml

+---
+stages:
+  - linting
+# Change pip's cache directory to be inside the project directory since we can
+# only cache local items.
+variables:
+  PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
+cache:
+  paths:
+    - .cache
+ansible-lint:
+  stage: linting
+  image: registry.gitlab.com/pipeline-components/ansible-lint:latest
+  before_script:
+    - pip3 install yamllint
+  script:
+    - ansible-lint .