Also fixed test events ordering issue

Now test events return the builds instead a list of pipelines to avoid calling pipeline.builds per each and get the info. Also, added missing fields/data, URLs, and fixed specs in events spec.

added missing fields to issue. Also, added a light url builder to add URLs easily from arel. Updated specs.

add pipeline id to merge request metrics table. Also, updated the pipeline worker to populate this field.

- Refactored cycle analytics class to extract DB logic
- Reuse logic in new events fetcher
- Started adding cycle analytics events class and spec (still not functional)