feat: add markdownlint-cli2 pre-commit hook to boilerplate output

mentioned in merge request uis/devops/experiments/tb844-testing/webapp!13 (closed)

mentioned in merge request uis/devops/iam/activate-account/api!55 (closed)

mentioned in merge request uis/devops/experiments/tb844-testing/webapp!16 (closed)

mentioned in merge request uis/devops/experiments/tb844-testing/webapp!18

mentioned in merge request uis/devops/iam/activate-account/api!164 (closed)

mentioned in merge request uis/devops/iam/activate-account/api!165 (closed)

mentioned in merge request uis/devops/experiments/tb844-testing/webapp!28

mentioned in merge request uis/devops/iam/activate-account/api!233

mentioned in merge request uis/devops/iam/activate-account/api!234