Add git-upload-archive

Add git-upload-archive

This command implements the git archive protocol on the server
side. This command is not intended to be used by the end user.
Underlying git-archive command line options are sent over the
protocol from "git-archive --remote=...", just like upload-tar
currently does with "git-tar-tree=...".

As for "git-archive" command implementation, this new command
does not execute any existing "git-{tar,zip}-tree" but rely
on the archive API defined by "git-archive" patch. Hence we
get 2 good points:

 - "git-archive" and "git-upload-archive" share all option
   parsing code.

 - All kind of git-upload-{tar,zip} can be deprecated.

Signed-off-by: Franck Bui-Huu <vagabon.xyz@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>