MAVLink: Update complete app to support MAVLink 1 & MAVLink 2. Add MAV_PROTO_VER param to switch between them

* mc pos control: in manual mode calculate attitude setpoint
such that it reflects the users intuition of roll and pitch
for any given heading error

* added some comments on the new manual attitude setpoint generation

* make calculation shorter

Incorporates big fixes for use of external vision data

Further updates to improve angular alignment consistency

fixes bug that can cause alignment to fail for pitch angles near +-90 deg

The sensors in the SITL environment are near ideal, so the
initialization in ekf2 can happen quicker.

Revert "Switch from EKF2 to LPE since SITL s is not any more a bearable workflow with EKF2 init lag"

This reverts commit 50396616.

adds ability to set initial tilt alignment uncertainty

This makes sure that adding & removing of .msg files is handled properly
by the build system.

This makes sure the .cpp file is regenerated on .msg file changes

minimum follow target alt of 8 m added, protecting against nan values in pos controller, fixing ci build error