find-remotes: Add pull support to the find-remotes built-in command
find-remotes: Add pull support to the find-remotes built-in command

This will pull the remotes after finding them. This potentially needs to
go in its own pull-from-remotes built-in command, but it will be fine
here for now.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Closes: #924
Approved by: cgwalters

GNOME/ostree,GNOME/ostree,GNOME/ostree,GNOME/ostree,GNOME/ostree