Copter reverse motors via Lua

[StenPetrov]

Feature request

I am building a demo drone that requires the ability to reverse its motors from a Lua script.
The ability to reverse exists, and is used for Turtle mode, but doesn't appear to be accessible via Lua
Previous work on reversible motors: #8579

My request is: Please provide ESC reverse API to Lua on AP Copter

Currently, to achieve the desired functionality I'd need to fork AP, clone its Turtle mode and alter it to allow reversing individual motors. That's an obvious problem for future compatibility, as my fork will likely go stale quickly.

Platform
[ ] All
[ ] AntennaTracker
[x] Copter
[ ] Plane
[ ] Rover
[ ] Submarine