closes#8037🔥 Remove API-level default settings population
- This is a relic!
- We ALWAYS populate defaults on server start therefore this code could never run.
- This was a lot of complicated code that wasn't even needed!!
🎨 Move settings cache
- Move settings cache to be its own thing
- Update all references
- Adds TODOs for further cleanup
🎨 Create settings initialisation step
- Create new settings library, which will eventually house more code
- Unify the interface for initialising settings (will be more useful later)
- Reduce number of calls to updateSettingsCache
