Add support for OAuth tokens

[haboustak]

GitLab 17.2 has added support for the OAuth Device Authorization Grant workflow.

We can use this new feature to implement an oauth token-type for art configure that can reduce or eliminate the need for private access tokens.

When employed, art configure -token-type oauth will prompt the user with a link to GitLab and a code to authorize access to their account. Once completed, the resulting oauth token can be written to the configuration file.