Add Doyu Studio DO60

[dunk2k]

Description

Despite being added to QMK in December of 2017, titular PCB is still available for purchase.

Titled keyboard was added to QMK in December 2017, with a VIA keymap added later.

QMK Pull Request

Initial merge: qmk/qmk_firmware#2120
VIA keymap: qmk/qmk_firmware#9622

Checklist

• The VIA support for this keyboard is MERGED in QMK master already (MANDATORY)
• The VIA definition follows the guide here: https://caniusevia.com/docs/layouts
• I have a V3 JSON version for this keyboard definition.(MANDATORY)
• I have tested this keyboard definition using VIA's "Design" tab.
• I have tested this keyboard definition with firmware on a device.
• I have assigned alpha keys and modifier keys with the correct colors.
• The Vendor ID is not 0xFEED

[casuanoob]

Whatever listing was at the PCB link seems to have been taken down

JSON looks fine to me

[dunk2k]

Whatever listing was at the PCB link seems to have been taken down

That's a shame, I hope it was due to selling stock rather than unavailability