gitweb: linkify author/committer names with search

It's nice to search for an author by merely clicking on their name in
gitweb. This is usually faster than selecting the name, copying the
selection, pasting it into the search box, selecting between
author/committer and then hitting enter.

Linkify the avatar icon in log/shortlog view because the icon is directly
adjacent to the name and thus more related. The same is not true
when in commit/tag view where the icon is farther away.

Signed-off-by: Stephen Boyd <redacted>
Signed-off-by: Junio C Hamano <redacted>