Console example doesn't duplicate code in `console` component.
Linenoise has been improved: it now has a parametrized command line
length. It is now possible to paste data efficiently to the console.
Note: this can only be done if the cursor is at the end of the line.
Closes https://github.com/espressif/esp-idf/issues/7057
1. Add command for Ethernet based on console component.
2. Make cmd_system and iperf a component that can be referenced by other examples
3. Add "version" command to cmd_system.c
4. Clean up the README.md in all ethernet examples[TW#26525]
