Add support for LED breathe speed

[Jigoku]

This feature doesn't exist in the Windows driver tool software, and stumbled upon this setting by chance.
Add a slider (find min/max values) and allow this to be customized.

[Jigoku]

Sending this write adjusts the breathing speed, where "ff" is speed.

07 0b 01 00 08 ff 00 00

Untested for now, but assuming 0x00 will turn off the LED, small increments such as 0x10 will cause slow breathing, and 0xFF being the maximum possible value, likely the keep the LED on at all times when set.