Proposition: add description and details of set variables in CLI #393

Instead of refering to the online docs each time we work in the CLI, typing meshtastic --get 0 could output the following structure:

display:
display.auto_screen_carousel_secs # time between screen pages rotation (seconds)
display.compass_north_top # impose compass orientation (bool)
display.flip_screen # orientation of oled screen (bool)
display.gps_format # format of lat, lon coordinates ("gpsFormatDec", "gpsFormatDms", ...)
display.screen_on_secs # Time to keep screen on (seconds)
display.units # .....

Having the description, setting value type and possible values and exceptions would be useful.