[PM-27280] Support v2 encryption on key-connector signups (#6712)

* account v2 registration for key connector

* use new user repository functions

* test coverage

* integration test coverage

* documentation

* code review

* missing test coverage

* fix failing test

* failing test

* incorrect ticket number

* moved back request model to Api, created dedicated data class in Core

* sql stored procedure type mismatch, simplification

* key connector authorization handler

src/Core/Services/Implementations/UserService.cs

@@ -621,6 +621,7 @@ public class UserService : UserManager<User>, IUserService
         return IdentityResult.Failed(_identityErrorDescriber.PasswordMismatch());
     }
 
+    // TODO removed with https://bitwarden.atlassian.net/browse/PM-27328
     public async Task<IdentityResult> SetKeyConnectorKeyAsync(User user, string key, string orgIdentifier)
     {
         var identityResult = CheckCanUseKeyConnector(user);