Improve user management

[leo-schick]

I did some work in order to improve the user management. This was requrested in #225 as well.

Task list:

• add request to get a single user from the Saas.Permissions API (GetTenantUser)
• add request to get a single user from the Saas.Admin API ({tenantId}/Users/{userId})
• adding views for Edit, Details and Delete (functionality for Edit and Delete are missing)
• finalize API to edit users (UI is alredy implemented but returns 404 NOT FOUND)
• finalize API to delete users (UI is alredy implemented but returns 404 NOT FOUND)
  Note: The delete function should not be able to delete the last admin user of a tenant (!)

[leo-schick]

@1iveowl maybe you could implement the missing API functions?

This PR could be be merged already now since it does not add any harm but just improves the currently incomplete implementation of the user management.

[1iveowl]

@1iveowl maybe you could implement the missing API functions?

This PR could be be merged already now since it does not add any harm but just improves the currently incomplete implementation of the user management.

Thank you @leo-schick. Current dev work is centeret around researching the introduction of Microsoft Entra External Id to replace Azure B2C. If you want to add the missing APIs please feel free to do so.

I will go ahead and merge what you have already created. Thank you for your contribution.