New RC Option: Force Flare (most useful for tilt rotors)

In master now, RC option 89, Force Flare.
Allows tilt rotors to belly land without breaking motors mounts by getting them up out of the way of the ground. Since tiltrotors can usually fly much longer in fixed wing modes, either by design or accident, one could fly longer than remaining battery voltage/capacity is capable of landing in VTOL. So this allows a belly landing without breaking a tilt mount by getting them out of the way.
Currently, it also set a fixed pitch target of LAND_PITCH_CD for a fixed flare and glide since this in intended to ultimately become part of the AUTOLAND sequence. However, a PR is pending to allow full pitch control ( ), since I found during extended flight testing on different platforms, its easier to manually land controlling pitch a few times, in order to actually determine the best value for LAND_PITCH_CD…and I actually now prefer the manual land most of the time.
If QAssist is setup, activating this switch will prevent entering it …kinda of defeats the purpose of landing…and if already in assist, activating this switch does nothing until assist is exited…
I tried to capture the action during real landing with a video camera, but getting the framing close enough and frame rate high enough to actually see it was difficult…so above is a Convergence SITL in RF9 illustrating its use…