[OSCBS-41] Update to Zephyr v3.2.0 (#382)

Updating to integrate with Zephyr v3.2.0 required:

- Update `west.yml` to import Zephyr v3.2.0 manifest
- Prefix include pathname of ztest.h with `zephyr/`
- Prefix every Zephyr header included pathname with `zephyr/`
- Change all Zephyr tests/samples to use `find_package`
- For unit_testing, use a distinct prj.conf which only references
  Kconfigs defined in the Zephyr repo. (Zephyr constraint.)
- Move ztest headers into a zephyr-prefixed pathname

Co-authored-by: Gregory Shue <gregory.shue@legrand.com>

test/bacnet/bacdevobjpropref/src/main.c

@@ -8,7 +8,7 @@
  * @brief test BACnet integer encode/decode APIs
  */
 
-#include <ztest.h>
+#include <zephyr/ztest.h>
 #include <bacnet/bacdcode.h>
 #include <bacnet/bacdevobjpropref.h>