Settings are loaded from the DB and added to the AppConfig during startup.
When updating settings, they are stored in AppConfig, and written do the database.
- updated dbdiagrams schema
- [BREAKING] force failure if `notify.filter_attributes` or `notify.level` is set
- added Settings table (and default values during migration)
- Added Save Settings and Get Settings functions.
- Added web API endpoints for getting and saving settings.
- Deprecated old Notify* constants. Created new MetricsStatus* and MetricsNotifyLevel constants.
Jason Kulatunga