Feature request: Read (pick) current RGB value of a key

[mfvianna]

This will allow querying the current RGB color of a key (suggested command option "-i" and profile "pick" directive, similar to "var"). Command example:
command: g810-led -i KEY_1
output: ffffff

This will be especially useful on profiles where one could clone a key color from another key. Example:

pick key1color KEY_1

k 2 $key1color

Would be very helpful for processes that, for example, change the letters colors based on capslock keypress or keypad number colors based on numlock keypress.

OBS: Would work o a patch for further PR, but I have no idea on how the protocol works and specific hidapi usage.