Add support for specifying login with domain name

Scenario:

The User1 is available in 2 different User Directories say UD1(domain1) and UD2(domain2). The User1 is part of Group1 from UD1 and Group2 from UD2. The Project & Repository permissions are granted based on groups.

Expectation:

• User1 should be able to login with username as <domain1>\User1 or User1@<domain1UPN> and should be able to access Project/Repository belonging Group1 only.
• Similarly, when User1 login with username as <domain2>\User1 or User1@<domain2UPN>, the User1 should be able to access Project/Repository belonging Group2 only.

Workaround:

None