feat: bulkdelete ban feature in forum

[mraman-2U]

This pull request introduces a comprehensive discussion ban management system to the forum API. It adds new API endpoints, serializers, and supporting backend integrations to allow moderators to ban and unban users at both course and organization levels, view ban details, and list banned users. The changes also include the necessary serializers for input validation and output formatting, as well as updates to backend model imports and project dependencies.

Discussion Ban API Implementation:

• Added new API endpoints for banning users, unbanning users, listing banned users, and retrieving ban details in forum/urls.py and implemented corresponding API views in forum/views/bans.py. These endpoints handle input validation, error handling, and interact with the ban management logic. [1] [2] [3] [4]

• Introduced serializers for ban-related operations in forum/serializers/bans.py, including BanUserSerializer, UnbanUserSerializer, and response serializers for consistent API input/output.

API and Backend Integration:

• Exposed new ban management functions (ban_user, unban_user, get_ban, get_banned_users, etc.) in forum/api/__init__.py for use by the API views and other modules. [1] [2] [3] [4]

• Added imports for MongoDB ban-related models (DiscussionBanExceptions, DiscussionBans, DiscussionModerationLogs) in forum/backends/mongodb/__init__.py to support future backend operations. [1] [2]

Dependencies:

• Added django-model-utils to requirements/base.in to support model features used in ban management (such as TimeStampedModel).Merge checklist:
  Check off if complete or not applicable:

• Version bumped
• Changelog record added
• Documentation updated (not only docstrings)
• Fixup commits are squashed away
• Unit tests added/updated
• Manual testing instructions provided
• Noted any: Concerns, dependencies, migration issues, deadlines, tickets

[jcapphelix]

Lgtm,

Before merging, do bump the version of forum, otherwise changes may not get reflected.