Adjustments to repo icon

The following visual adjustments have been made:
- Make color similar to other icons in the metadata panel.
- Highlight on hover to convey interactivity.
- Adjust to the "visual center". The icon was matematically centered, but since the angular separator adds empty space to the right, a 2px correction has been added so that it looks centered taking into account that extra space.

Change-Id: Ib4db723b38a8d6fc9528fe86756220b6525da95b