Initial LinkedIn v2 API authsource

README.md

attributemap/linkedin2name.php

docs/GOOGLE.md

docs/LINKEDIN.md

lib/Auth/Source/LinkedInV2Auth.php

lib/Auth/Source/MicrosoftHybridAuth.php

lib/Auth/Source/OAuth2.php

lib/ConfigTemplate.php

lib/OAuth2ResponseHandler.php

tests/lib/Auth/Source/LinkedInV2AuthTest.php