add a pushurl to the remote AGL using ssh config

add a pushurl to the remote AGL using ssh config

 * by default repo use a anonymous http URL to fetch the agl remote.
   But the same URL is used to push review or/and sandboxi to gerrit.
   The anonymous http URL can be only use on read only conf.
   Add a pushurl ("pushurl="ssh://gerrit.automotivelinux.org:29418") to the agl remote allow
   user to push (write) on is own ssh account.

   If your user have a diff name than your user gerrit acount:
   #cat ~/.ssh/config
      Host gerrit.automotivelinux.org
       User XXXMyGerritNameXXX

Change-Id: I89c80943bd1b22838215b833a34c42ff7afa206c
Signed-off-by: Ronan Le Martret <ronan.lemartret@iot.bzh>