[BUG] Fix configs to support multi-tenancy #346
Description
Describe the bug
The current implementation of ApplicationConfig does not support multi-tenancy. Only one application config is used (based on environment variables), so any functions using data from an ApplicationConfig will not support multi-tenancy.
Expected behavior
Implement the configs collection solution from https://github.com/rokwire/building-block-template-go and add Type, AppID, and OrgID fields to support multi-tenancy. Also, a System flag should be added to configs to allow system-level users to control which configs may be modified by lower-level admins. SyncConfig and ManagedGroupConfig should both be stored in the configs collection.