Background:
When adding a scope by a tenant, the user is able to select multiple definitions and add them at once.

AT:

• Create an additional add scope endpoint to support adding multiple scopes
• When multiple scopes are provided they are atomically merged with the existing ones, which means:
  • Do not return any conflicts if the user adds a scope for a definition (unique combination of type and key) that already exists
  • for an existing scope, if users select an additional tenant, then just add that (perform an update) (idempotent)
• the endpoint is documented in the collection scope api documentation
• the endpoint is a PUT endpoint as it will have PUT semantics (idempotent)
• there is a front-end follow up ticket to use this endpoint -> OPT-2926

Hints:

• The order of the scopes/tenants does not matter during the adding since the front-end always reloads the scopes using the get scopes endpoint after adding the scopes anyway.
• We keep the old add scope endpoint for backwards compatibility. It will be removed with OPT-2906