Added anti-turtle reversemotors and beeper using dshot commands on blheli_s #3267
Needs my branch of blheli_s to use the commands.
Used new commands 20 and 21 because I'm unsure how kiss esc will act. I don't have one to test with commands 7 and 8 that are similar. Currently 21 reverses motors from the blheli programmed direction and 20 returns it to the programmed direction.
Reusing BOX3DDISABLESWITCH to switch motors. Only switch when disarmed, settings are not saved on the ESC.
I'm anticipating a few more changes so I'll squash commits when finished. Looking for input..
Please please test props off first to make sure motors are working as expected!