Add OAuth2 bearer token

[sh-hilden]

I add OAuth2 Authentication: https://docs.gitlab.com/ce/api/oauth2.html

[ngetchell]

How does one generate the Bearer token used in the new functionality? Private Tokens can be generated via UI but I can't seem to find anything that would help you get one.

If the only way to get a bearer token is via an API call I think we need to add a function to get a bearer token.

[sh-hilden]

Yes you can get it via the OAuth API. See here: https://docs.gitlab.com/ee/api/oauth2.html#resource-owner-password-credentials-flow