This change converts the `approve_unless_trust_level` site setting to
`approve_unless_allowed_groups`.
See: https://meta.discourse.org/t/283408
- Adds the new site setting
- Adds a deprecation warning
- Updates core to use the new settings.
- Adds a migration to fill in the new setting of the old setting was
changed
- Adds an entry to the site_setting.keywords section
- Updates many tests to account for the new change
After a couple of months we will remove the `approve_unless_trust_level`
setting entirely.
Internal ref: /t/115696
447d9b2105