impl/65258 Define Comments Services and Contracts for Commented models `News` and `WorkPackage`

[akabiru]

https://community.openproject.org/work_packages/65258

Define Comment CrUD services and contracts

• [x] #19361
• [x] Defines created and update services with the supporting contracts and attribute service
• [x] Make WorkPackage commentable
• [x] Add Comment#internal for internal comments functionality, with corresponding contract and permissions checks
• [x] Update existing News::CommentsController to use new services

[github-actions[bot]]

[!CAUTION] The provided work package version does not match the core version

Details:

• Work package URL: https://community.openproject.org/work_packages/65258
• Work package version: not set
• Core version: 16.4.0

Please make sure that:

• The work package version OR your pull request target branch is correct