[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/ztest/src/ztest.c

@@ -4,9 +4,9 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-#include <ztest.h>
+#include <zephyr/ztest.h>
 #include <stdio.h>
-#include <tc_util.h>
+#include <zephyr/tc_util.h>
 #if 0
 #include <app_memory/app_memdomain.h>
 #ifdef CONFIG_USERSPACE
@@ -15,7 +15,7 @@
 #endif
 
 #ifdef KERNEL
-#include <sys/reboot.h>
+#include <zephyr/sys/reboot.h>
 static struct k_thread ztest_thread;
 #endif
 

test/ztest/src/ztest_error_hook.c

@@ -3,8 +3,8 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
-#include <zephyr.h>
-#include <ztest.h>
+#include <zephyr/kernel.h>
+#include <zephyr/ztest.h>
 
 
 #if defined(CONFIG_ZTEST_FATAL_HOOK)

test/ztest/src/ztest_mock.c

@@ -13,7 +13,7 @@
 #ifdef KERNEL
 #error Why is KERNEL defined by hered?
 #endif
-#include <ztest.h>
+#include <zephyr/ztest.h>
 #ifdef KERNEL
 #error Why is KERNEL defined by hered?
 #endif