* Made voxl2 apps processor and slpi dsp processor builds into separate board builds so that they can
more easily be configured independently.
* Removed board specific link library command from px4_config.cmake and moved it to a more generic
board specific solution that can be used by any board that needs custom link libraries.
* Removed redundant cmake command for Qurt
* Removed unused definition from Qurt cmake file
* Removed unnecessary QURT_LIB cmake function
* Reorganized the voxl2 build structure to avoid 4 level board directories.
* Reverted cmake files to remove 4 level board naming code
* Updated documentation
* Removed dprintf from perf library since it is only ever used with fd=1 (STDOUT) so moved to PX4_INFO_RAW instead. This helps with some platforms (e.g. Qurt) which have some Posix support but not full Posix support.
* Removed exit after dsp signature generation.
* First full test suite
* Cleaned up the muorb tests
* Improved VOXL 2 self test trigger in startup file
* Removed unneeded include file
Eric Katzfey