* Add APDU as NULL to get BACnet type lengths.
* Fix bacapp copy test to succeed
* fix BACnet REAL and DOUBLE decode
* Add unit test for NULL APDU encoding for length
* Add unit tests for bacapp context
* refactor host-n-port to hostnport.c module
* fix BVLC decoder
* additional unit testing for bacapp
* include bacdevobjpropref module in builds
* simplify bacapp snprintf to be able to return length
* adjust compiler for variable-length arrays
* fix bug found by scan-build
Authored-by: Steve Karg <skarg@users.sourceforge.net>
* Leverage (older) embedded unit tests into external unit tests build upon copy of Zephyr's ztest library and CMake.
* Expand top-level CMake build to run external unit tests.
* Expand Zephyr module extension to run external unit tests via west or sanitycheck.
Co-authored-by: Gregory Shue <gregory.shue@legrand.us>