Copter: add new setting for final landing vspeed instead of being hardcoded to 25% of set landing vspeed

[shellixyz]

Tested, seems to work fine

Configurator part: iNavFlight/inav-configurator#1235

Testing video:

Settings:
set nav_landing_minalt_vspd = 50
set nav_landing_maxalt_vspd = 300
set nav_land_slowdown_minalt = 200
set nav_land_slowdown_maxalt = 1000

https://youtu.be/3pynEufaYqE

[stronnag]

@shellixyz Michel,there's a couple of places in settings.yaml where the 25% is mentioned explicitly in the description: nav_land_slowdown_minalt, nav_land_slowdown_maxalt. The description should be amended to reference the nav_landing_minalt_vspd setting instead of hard-coded 25%.

[shellixyz]

@shellixyz Michel,there's a couple of places in settings.yaml where the 25% is mentioned explicitly in the description: nav_land_slowdown_minalt, nav_land_slowdown_maxalt. The description should be amended to reference the nav_landing_minalt_vspd setting instead of hard-coded 25%.

Thank you @stronnag, should be good now