Add filters for tags

• Uses the existing implementation of highlighting revisions from the same user
• Shows bubble next to tags in Tooltip
• When you hover on a bubble, tag row is circled, and revisions with a specific tag gets highlighted. When hovering ends, highlighting ends. But, if there is an active filter available, all previous states are restored accordingly.
• When you click on a bubble, in addition to highlighting revisions and tag row, any previous tag or user filter is removed.

Bug: T203581
Change-Id: I824a027a7f542eb7227545870553e58ec23542bb