RFC-214: Repository Settings > Mirroring should not display token in the UI

Created by: unknwon

We currently display the full clone URL (including the token) in the repository Settings > Mirroring page, we should stop doing that.

I didn't verify, but it feels like we need to:

1. Find where the backend returns the value of this field in GraphQL.
2. Use url.Parse and wipe out the username and password portion, which effectively makes it a normal-looking URL (in a browser address bar).