Implementation Plan: Django admin moderator access control and base i…

…mprovements (#3494)

* Implementation Plan: Django admin moderator access control and base improvement

* Proofread and clarify

* Fix reference to other markdown file

* Revise plan

* Remove pre-existing bulk update from report model save methods

* Update documentation/projects/proposals/trust_and_safety/content_report_moderation/20231208-implementation_plan_django_admin_moderator_access.md

Co-authored-by: Staci Mullins <63313398+stacimc@users.noreply.github.com>

* Clean up list formatting and remove stale sentences

* Deduplicate report status in favour of decision action

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Co-authored-by: Staci Mullins <63313398+stacimc@users.noreply.github.com>