BriarService currently ignores startup errors

See briar#2089

• lifecycleManager.startServices(dbKey) is currently called directly from Login.kt and Registration.kt and indeed ignores startup errors
• this issue should be addressed after properly restructuring those calls into another class (e.g. BriarService)

List of encountered errors:

• org.briarproject.bramble.api.db.DataTooNewException