DEV: Convert min_trust_to_create_topic to groups (#24740)

This change converts the min_trust_to_create_topic site setting to
create_topic_allowed_groups.

See: https://meta.discourse.org/t/283408

- Hides the old setting
- Adds the new site setting
- Add a deprecation warning
- Updates to use the new setting
- Adds a migration to fill in the new setting if the old setting was
changed
- Adds an entry to the site_setting.keywords section
- Updates tests to account for the new change
- After a couple of months, we will remove the min_trust_to_create_topicsetting entirely.

Internal ref: /t/117248

spec/lib/topic_view_spec.rb

@@ -3,7 +3,7 @@
 require "topic_view"
 
 RSpec.describe TopicView do
-  fab!(:user)
+  fab!(:user) { Fabricate(:user, refresh_auto_groups: true) }
   fab!(:moderator)
   fab!(:admin)
   fab!(:topic)