scripts: zephyr: separate from server dir

Move the zephyr start scripts from server dir to root directory. The
scripts are used for testing and are not directly related to the server
implementation.

Signed-off-by: Jonas Remmert <jremmert@gmx.net>

doc/source/documentation.rst

@@ -159,8 +159,7 @@ components locally. Once leshan and Zephyr are running, the Zephyr application
 can be started in emulation with the following command:
 
 .. code-block:: console
-
-  host:lwm2m_server/server$ zephyr_build_run_sim.sh
+  host:lwm2m_server$ zephyr_build_run_sim.sh
 
   *** Booting nRF Connect SDK zephyr-v3.5.0-3024-g7c3e830729b7 ***
   [00:00:00.000,000] <dbg> net_lwm2m_engine: lwm2m_engine_init: LWM2M engine socket receive thread started

zephyr_build_run.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+## Build and run Zephyr
+west build -p=auto -b qemu_x86 fw_test/lwm2m_client -p -- -DCONF=overlay-lwm2m-1.1.conf
+west build -t run

zephyr_build_run_sim.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+# Function to stop networking
+cleanup() {
+    ../tools/net-tools/net-setup.sh stop
+}
+
+# Register the cleanup function to be called on the EXIT signal
+trap cleanup EXIT
+
+# Start networking via net-tools
+../tools/net-tools/net-setup.sh start
+
+## Build and run Zephyr
+west build -p=auto -b qemu_x86 ../zephyr/samples/net/lwm2m_client -- -DCONF=overlay-lwm2m-1.1.conf
+west build -t run
+
+cleanup