Switch assignment: added manual and stabilized switch for a default stabilized switch scheme, let FW go into Acro

* Fix several valgrind identified mem leaks

* Added callgrind target.

* px4_posix_tasks use nullptr

We need to protect access to the param_values array. This is dynamically
allocated and resized (utarray_reserve() calls realloc). If some thread
was iterating the array while another was resizing the array, the first one
would iterate on a freed array, thus accessing invalid memory.

On NuttX this could lead to hardfaults in rare conditions.

Unfortunately we need to initialize the semaphore on startup, by calling
sem_init(). This adds a param_init() method called by every board/config
that uses the params (at least I think I've found all of them)

This call is not needed, and will avoid deadlocks when locking is enabled.

This will ensure proper locking.

locking will be done in the params module

These changes were required to fix support for the ICM-20608 after this commit:

https://github.com/PX4/Firmware/commit/f746141afe3499ae56e75b3db06409381ead2f4b

This has been tested!

We buffer the mavlink messages and don't forward them directly
via uORB. This solves an issue where many requests are dropped and
QGC does not start properly in combination with UAVCAN devices.

Also change the initial state of the leds to off.