Support minimal API commands also through ssh

Description

All users have working authentication in cli with ssh keys, thus the best way to automate things on the user/developer side is through ssh. It would be nice if gitlab would support some basic commands for user/developer side scripting. eg. list projects, maybe show their permissions for the connecting user (though that's not necessary, just a list would be fine too).

Both gerrit, gitosis and gitolite support commands through ssh, it would be nice if scripts could be ported to gitlab.

eg. it's nearly impossible to get every user to create an auth token for whatever he needes when he already has an ssh key which is both well protected and has the whole chain set up. Eg. for the auth token there is no protection at rest, no security on the client side per default which means a whole lot of work if operations want to go down that route.

Proposal

At least provide a list project API on the ssh side which shows all projects in a group give as argument

ssh git@gitlab.com ls-project <group>

Links / references

gitolite: http://gitolite.com/gitolite/gitolite.html#user

gerrit: https://gerrit-review.googlesource.com/Documentation/cmd-index.html