It implicitly converted STRINGS to STRING.

 - starts requirements for PX4 modules (hrt, param, etc)

Instead of using the define __PX4_POSIX_SITL it makes more sense to have
a define just to determine if the lockstep scheduler should be used.

- only a few configs done yet

 - add to AddressSanitizer and UndefinedBehaviorSanitizer to CMAKE_BUILD_TYPE options
 - handle environment variable helpers outside of CMake
 - add -O1 optimization
 - cleanup whitespace

 - px4_add_module now requires MAIN
 - px4_add_library doesn't automatically link

Generates an enum with all params & additional type information for static
type checking

The generated public param header is required to build the modules using
the new BlockParam classes.

Use like this:
	  make px4fmu-v2_default uorb_graph