Enable smart HTTP under /p/ URLs

The new smart HTTP Git protocol is now supported through the Gerrit
web application context by using the URL /p/$project.git.

Like SSH, push requires user authentication.  However, since
user authentication is currently based solely upon HTTP cookies,
and cookies aren't supported by the C Git command line client,
using push is not currently possible.  We need to introduce our
own password based user authentication process.

Change-Id: I76a894226a583ce6f47fd246f7d0f88b77ea4505
Signed-off-by: Shawn O. Pearce <sop@google.com>
5 files changed