net: samples: ot: Add configuration file for echo_client OT RCP HOST (UART)

This config allows setting up the echo_client program with
RCP HOST UART (via SPINEL protocol) communication.

Signed-off-by: Lukasz Majewski <[email protected]>

Author: Lukasz Majewski

samples/net/sockets/echo_client/overlay-ot-rcp-host-uart.conf

@@ -0,0 +1,59 @@
+CONFIG_REQUIRES_FULL_LIBC=y
+
+# CPP library
+CONFIG_CPP=y
+
+# Disable TCP and IPv4 (TCP disabled to avoid heavy traffic)
+CONFIG_NET_TCP=n
+CONFIG_NET_IPV4=n
+
+CONFIG_NET_IPV6_NBR_CACHE=n
+CONFIG_NET_IPV6_MLD=n
+CONFIG_NET_CONFIG_NEED_IPV4=n
+CONFIG_NET_CONFIG_MY_IPV4_ADDR=""
+CONFIG_NET_CONFIG_PEER_IPV4_ADDR=""
+
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=8192
+CONFIG_MAIN_STACK_SIZE=32768
+CONFIG_INIT_STACKS=y
+
+# Enable OpenThread shell
+CONFIG_SHELL=y
+CONFIG_OPENTHREAD_SHELL=y
+CONFIG_SHELL_STACK_SIZE=8192
+
+CONFIG_NET_L2_OPENTHREAD=y
+
+# Use NVS as settings backend
+CONFIG_NVS=y
+
+# Enable Openthread rcp host
+CONFIG_HDLC_RCP_IF=y
+
+# Enable OpenThread features set
+CONFIG_OPENTHREAD_THREAD_STACK_SIZE=8192
+CONFIG_OPENTHREAD_THREAD_VERSION_1_3=y
+#CONFIG_OPENTHREAD_DEBUG=y
+#CONFIG_OPENTHREAD_L2_DEBUG=y
+#CONFIG_OPENTHREAD_L2_LOG_LEVEL_INF=y
+
+# mbedTLS tweaks
+CONFIG_MBEDTLS_SSL_MAX_CONTENT_LEN=768
+
+# A sample configuration to enable Thread Joiner, uncomment if needed
+CONFIG_OPENTHREAD_JOINER=y
+
+# Enable diagnostic module, uncomment if needed
+#CONFIG_OPENTHREAD_DIAG=y
+
+# To have OTBR On-Mesh address assigned (fd11:22:0:0:)
+CONFIG_OPENTHREAD_SLAAC=y
+
+# Setup the communication to echo-server
+CONFIG_NET_CONFIG_PEER_IPV6_ADDR="fd11:db8:1::1"
+CONFIG_NET_CONFIG_INIT_TIMEOUT=60
+
+# Configure the OpenThread manually
+CONFIG_OPENTHREAD_MANUAL_START=y
+
+CONFIG_EVENTS=y