Add link to watching on GitHub

[JakeSidSmith]

It'd be useful to have a link to repos you're watching on GitHub from inside Gitify. Just as an easy way to customise what notifications you get.

[mikesmayer]

yes, is this capability forth coming?

[bmulholland]

This looks to be an uncommon request for a UI addition that maybe helps with rare workflows, but isn't core to what Gitify does. You can get to this link easily in many other ways, there's no need for Gitify to add UI complexity for it. See also #655