Add support for DCTTech USB relays hardware

[XVilka]

It is probably most common and cheapest USB relay on the market

It has USB VID:PID: 16c0:05df

See https://github.com/rfael/usbrelay-rs/blob/main/src/usbrelay.rs

Also see https://github.com/darrylb123/usbrelay

• https://sigrok.org/wiki/Dcttech_usbrelay
• http://sigrok.org/gitweb/?p=libsigrok.git;a=tree;f=src/hardware/dcttech-usbrelay
• https://github.com/u1f35c/usb-relay-firmware

[charlieh0tel]

Please send PR.