Extract Git /p/ module configuration

Move the configuration into its own module, this will make it easier
to control whether or not the Git access over HTTP is even installed
in a running server, or how it permits access.

Change-Id: I54074dbac96d47f32d444565993823f54348d722
Signed-off-by: Shawn O. Pearce <sop@google.com>
6 files changed