Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/29539

Document and remove unused code

Declare components in a consistent way;
Use " instead of ' to improve consistency;
Update documentation;
Fix commit author verification to match the use cases;

Adds tests for the added components

Fix paths in pagination spec

Adds tests to pipelines table used in merge requests and commits

Use same resource interceptor

Fix eslint error