RGH handles only one API Token #1714

Currently if you use RGH on a different domain and GitHub, as soon as you provide a token, the other site no longer works (as expected).

features.js:79 RefinedGitHubAPIError: The token seems to be incorrect or expired. Update it in the options.
    at call (chrome-extension://mnoacfgkaplmhhcgdnekddifjfcllloj/content.js:2481:11)
    at <anonymous>

We need to add the option to specify what URL the token is for and only use it for that domain. This becomes more important if #1713 is merged.