SITL: add base class for serial rangefinder simulators
SITL: add Benewake rangefinder simulator
SITL: add support for simulated LightWareSerial rangefinder
SITL: add support for simulated Lanbao rangefinder
SITL: add support for simulated BLping rangefinder
SITL: add support for simulated LeddarOne rangefinder
SITL: add support for simulated uLanding rangefinders
SITL: add support for simulated MaxsonarSerialLV rangefinders
SITL: add support for simulated Wasp rangefinders
SITL: add support for simulated NMEA rangefinders
For the general case, pragma once is better replacement for of include
guards. One line instead of three, less scopes to close in the end of
the file, no chance to having the outdated names in the define symbol.