Show tags which contain a given commit in their own metadata row on the commit page widget

Related to gitlab-ce#25998

Currently when you visit a commit page, the list of branches in which the commit appears will be loaded in via ajax but it can often be somewhat large.

I propose we move the tags into their own separate row and automatically display the oldest tag (this is usually the most pertinent):

Now I can see at a glance that this commit's first inclusion in a release was v8.15.0-rc1.