[actuators] start to rework actuators

- use multiple drivers at the same time
- all actuators firmware independant
- default actuators can still be defined for some boards
- only lpc part modified yet
- for now microjet example is compiling...
[submodules] changed libopencm3 url to the github repo via https
[feature] ahrs_dcm_float uses magnetic heading while not inflight for better initial guess
[fixedwing][feature] AP and FBW on different boards connected via Uart
* with example airframe and updated outdated airframes
* renamed spi version and make it a separate subsystem (e.g. 2 twogs)
[fixedwing][fix] includes for link_mcu_spi
update default version to v4.9_devel
[OBC] Outback Challenge Safety Rule 1
[OBC] Outback Challenge Safety Rule 2: Irreversible crash
yapa_2.0 board files
[actuators] more actuator drivers with new interface
[energyctl] save gains
[fix ap-fbw] sim now compiles
[fix] no error when missing a airframe parameter in energy-ctrl
[sw/ext] removed stm32loader submodule and added the files to sw/tools
source files should not be executable
removed some long deprecated subsystem makefiles
[actuators] first test with 2 drivers

- actuators are now in signed int16 (need to check size again) (int32 ?)
- servo_switch module replaces booz_drop
- booz_pwm is now handled by actuators_direct
[dox] generated doxygen html docs go to doc/generated/html by default, removed useless make target
[dox] latex formulas and dot graph in doxygen for energy_ctrl
[actuators] servo_switch directly controls actuators again