* Add more test cases for GetGitHubLoginUrl tests
* Fix enterprise authorize Urls by replacing the existing relative Uri segment (/api/v3) instead of appending to it via an extension method
* Add tests for new ReplaceRelativeUri extension method
* add test for GHE URL on oauth CreateAccessToken
* move away from class level consts
* Oauth client can store stripped base URL so it works with GHE