examples: freemodbus add tcp support for common master/slave iface

Add TCP port files to provide Modbus TCP interface for communication
Add freemodbus add tcp support for common master/slave iface and tcp example based on socket API
The communication between master and slave checked for each example serial_master, serial_slave (use ModbusPoll TCP)
update tcp example according netif changes, fix ci issues
update TCP slave implementation
update example_test.py to to set IP through stdin
update API documentation
event bit instead of semahore to lock communication resource
update default options and master/slave port files

Closes https://github.com/espressif/esp-idf/issues/858
Closes IDF-452

examples/protocols/modbus/tcp/mb_tcp_master/main/Kconfig.projbuild

@@ -0,0 +1,16 @@
+menu "Modbus TCP Example Configuration"
+
+    choice MB_SLAVE_IP_RESOLVER
+        prompt "Select method to resolve slave IP addresses"
+        help
+                Select method which is used to resolve slave IP addresses
+                and configure Master TCP IP stack.
+
+            config MB_MDNS_IP_RESOLVER
+                bool "Resolve Modbus slave addresses using mDNS service."
+
+            config MB_SLAVE_IP_FROM_STDIN
+                bool "Configure Modbus slave addresses from stdin"
+    endchoice
+
+endmenu