V2 adds:
* Independent result for visibility (showing/hiding menus)
* Includes adding IDs for all items (menus & symbols) in kconfig_menus.json
Still backwards compatible with V1, with some small changes (menu items now listed in results).
Also added some protocol docs, changed the "listening on stdin" message to come after any kconfiglib warnings
When generating JSON metadata for ranges where there are conditional ranges (ie different allowed range
depending on another config setting), the JSON metadata would always have the last named range as
the expression was not evaluated properly.
Thanks to ulfalizer on GitHub for pointing this out.
Closes https://github.com/espressif/esp-idf/issues/2195
