Add link to suggested reviewer MR dashboard

Prior to this change, it was hard to estimate how much MRs a person had assigned for review. Also, there were no reviewers suggested if the MR was assigned to yourself already.

This change adds a link to the suggested reviewer's MR dashboards. These dashboard show the MRs assigned to them, but authored by someone else. This should give an indication of how many reviews they have on their plate already.

The reviewers suggestion will now also no longer disappear, and we use the MR IID to seed the random number to suggest reviewers, which should give the same names every time.