Share common definitions in Review and ReviewCreate

[PGijsbers]

Change

Refactor class hierarchy to allow Review and ReviewCreate share common definitions, s.t. we only need to define examples or limits once.
Also limit the maximum length of review to LONG (1800 chars).
I think that should be enough for most asset reviews, and it's easier to expand the limit than to shrink it.

How to Test

Changes are under unit test. Affected endpoints is RESOURCE/review/v1/ if you want to manually test or inspect updated documentation.

Checklist

• Tests have been added or updated to reflect the changes, or their absence is explicitly explained.
• Documentation has been added or updated to reflect the changes, or their absence is explicitly explained.
• A self-review has been conducted checking:
  • No unintended changes have been committed.
  • The changes in isolation seem reasonable.
  • Anything that may be odd or unintuitive is provided with a GitHub comment explaining it (but consider if this should not be a code comment or in the documentation instead).
• All CI checks pass before pinging a reviewer, or provide an explanation if they do not.

Related Issues

[Taniya-Das]

I can see the comment field in `/submissions/v1/{identifier}, but no way for the user to submit a comment when sending an asset for review.

[PGijsbers]

Ah, I accidentally left the comment for submissions in there.. this was meant to be for the reviewer comment only. I'll update the PR to simply also include the submission comment. Thanks!

[PGijsbers]

I updated the PR to allow users to also submit a comment (in the body). Might move the identifier also to the body, but that will be a next PR -- I want to move the submission endpoint for all entities to the review router instead of making them entitiy-specific.

[Taniya-Das]

Looks good to me!