It provides more useful information for causual Git users than the Git docs
(especially about where to get Git and such).

People can override with GITWEB_CONFIG if they want to.
Signed-off-by: NPetr Baudis <pasky@suse.cz>
Signed-off-by: NJunio C Hamano <junkio@cox.net>
Acked-by: NPetr Baudis <pasky@suse.cz>