Convert comments to be revisionable

Seems to be some failures in the MR2872

Also the update hook will need upgrade tests.

Probably should update comment_user_cancel() so that revision_uid is re-assigned to zero (0) when the author's account is cancelled. I recently ran into an issue where the comment was re-assigned but not the revision. See node_user_cancel() as an example:

node_mass_update($vids, [
  'uid' => 0,
  'revision_uid' => 0,
], NULL, TRUE, TRUE);

Re-rolled for 10.3.x

Hey @robbiehobby does your re-roll in #79 include your proposed change in #78?

robbiehobby → changed the visibility of the branch 11.x to hidden.

Opened a new merge request for version 11.x. It includes several bug fixes, improvements, and test adjustments. I did my best to model all changes based on pre-existing solutions in the node revisions implementation.

I haven’t figured out how to resolve the core/modules/jsonapi/tests/src/Functional/CommentTest.php test. Maybe someone who is familiar with that test can jump in? The other failing tests do not seem related to these changes, but I could be wrong.

There probably needs to be new tests created for comment content moderation and for the user cancel changes. Unfortunately, I won’t have time to work on these immediately. Please feel free to jump in if you'd like.

1. Added the missing revision keys to the config and tests.
2. Added the revision UI, links, and access control.
3. Kept the existing comment permission structure with administer comments being the permission that can perform revision CRUD operations.
4. Removed the base field alter hook because this should be configured in the content moderation workflow rather than in the code.
5. Added shared table indexes for the comment_revision table.
6. Created comment_mass_update, a carbon copy of node_mass_update, to primarily handle hook_user_cancel operations gracefully. It includes a new $syncing option to prevent the creation of new revisions when reassigning comments to the anonymous user account. A similar issue for nodes exists at [ https://www.drupal.org/project/drupal/issues/3062900] → ( https://www.drupal.org/project/drupal/issues/3062900 → ).
7. Added a comment moderation handler.
8. Updated the comment links renderer to be aware of revisions.

not reviewed yet but pipeline appears to have test failures.