[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>

ports/zephyr/bacport.h

@@ -26,9 +26,9 @@
 #ifndef NET_H
 #define NET_H
 
-#include <net/net_ip.h>
-#include <net/socket.h>
-#include <zephyr.h>
+#include <zephyr/net/net_ip.h>
+#include <zephyr/net/socket.h>
+#include <zephyr/kernel.h>
 #include <bacnet/basic/object/device.h>
 
 static inline char *inet_ntoa(struct in_addr in) {