Rewrite gerrit gitweb URLs to new gitblit

This replaces the rewrite rule for message URLs with something more
general that handles p=project and p=project;f=file URLs.
It works on my local Apache instance.

Bug: 41961
Change-Id: If02ce0fe0ddd8a9b692a0d2526bdbed27a762fc4
Merge "Rewrite gerrit gitweb URLs to new gitblit" into production