Implement revisions tab (Step 4)(Iteration N)
<!--IssueSummary start-->
<details>
<summary>
Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards.
</summary>
- [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=39271)
</details>
<!--IssueSummary end-->
**Important:** All the new functionality must be implemented behind the feature flag `:version_snippets`. Besides, it has to be scoped for projects. Therefore, instead of checking if the feature flag is enabled or not (`Feature.enabled?(:version_snippets)`), we will check if the feature flag is enabled for specific users (`Feature.enabled?(:version_snippets, user)`).
## UX Proposal
Add a `Revisions tab`
* Display a list of revisions when the user clicks the `Revisions tab`
* For each revisions display:
* Avatar of the user that made the revision
* Name of the user that made the revision
* When the revision was made
* Count of files, added lines, removed lines
* The associated diffs
* Diffs are displayed expanded by default but should be collapsable
* Load the 5 most recent revisions
* If more than 5 revisions exist, show pagination controls to load additional
| Description | Mockup |
| ------ | ------ |
| Revisions tab |  |
## Availability and Testing
Potentially requires E2E coverage
### Security Testing
* Ensure visibility of revisions (@lulalala )
### Testing Activity
* Test to check that we display the information we need (@fjsanpedro)
### QA Testing
This change warrants a new end-to-end test, new issue for it to be created and linked (@a_mcdonald).
NB Please include the SET (@a_mcdonald) in your MR reviews to coordinate the progress.
issue