awesome: autostart applications from awesome

Ideally I had hoped that I could have a more logical tree structure
where awesome, the window manager starts before the clients. It seems to
have been backwards when xinit was responsible for spawning autostarts.

However, doing it this way seems to have resulted in awesome dropping
the spawns which are caught by PID1 (as seen in htop/pstree).

I don't think this is a big deal, but it's also not great.