New boot animation for 12.1.0

[Mikus Grinbergs]

I do not think the two-step progression from one dot to three dots is 
very useful.  Particularly since on an XO with 21005xx1 with both an USB 
hub and an USB-ethernet adapter plugged in, "pretty boot" stalls with 
the one dot showing.  [No change after 30 minutes;  no clue as to what 
the user should do now.]  Note - the same setup with pressing the check 
button (_no_ pretty boot) will boot correctly to completion.

Please consider replacing the dots with a constantly-moving indicator 
(perhaps like in Object Chooser), but which STOPS when booting stalls.

Thanks,  mikus