[Feature] Change gkey color for mapped keys

[suabo]

It would be cool to use g810-led so that gkeys change to a defined color when they are assigned to something else then nothing. This is especially useful when using profiles. There would also be the possibility to make a new entity in the config of the gkeys to define a color for every macro like so:

"g2": {
    "hotkey_type": "shortcut",
    "do": "alt+F4",
    "color": "ff0000"
},

The original Idea was from the author him self. I just added it here to keep track of things and maybe get some feedback on this.