builder: remove hob from autostart

builder: remove hob from autostart

hob has been removed so don't try and autostart it with the mini-x
session in the build appliance.

Remove the please_wait_dialog program which informed the user to
wait for Hob to start.

Rename the mini-x autostart file to reflect the removal of hob, we
now just start a matchbox-terminal with the environment configured.

Signed-off-by: Joshua Lock <joshua.g.lock@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>