Processes: Create ActivateSingleInstance Process

[Phil91]

Description

The current synchron processes to activate an single instance offer should be made asynchronous. Therefore the current processes implemented in ActivateSingleInstanceAppAsync should be moved into an own processes. The process should be placed into a new OfferHandling Process project.

Acceptance Criteria

• New process project OfferHandling in place
• New process to set the instance type
• All process steps have retrigger steps where it makes sense

Additional Information

Proposed split would be EnableClient, CreateCentralOIDCClientAudienceMapper, CreateTechnicalUsersForOffer, ActivateDatabaseOffer

Linked to: #1006