Exposes endpoint for revoking/deregistering access tokens needed for deregistering users in the PushEndpoint https://github.com/RADAR-base/RADAR-PushEndpoint/pull/11 at DELETE source-clients/{type}/authorization/{serviceUserId}
Adds endpoint for getting user by serviceUserId at GET source-clients/{type}/authorization/{serviceUserId}
Separate user deletion implementations for different auth types (so that Garmin auth can immediately delete while Fitbit auth can revoke first before deleting)
Change Garmin deregistration endpoint to immediately delete the user
DELETE source-clients/{type}/authorization/{serviceUserId}
GET source-clients/{type}/authorization/{serviceUserId}
Partially solves https://github.com/RADAR-base/RADAR-PushEndpoint/issues/12