Added support for Keychron Q12

[KeychronMacro]

Added support for Keychron Q12.

Description

• Add VIA JSONs for Keychron Q12.

1. Add ANSI and ISO versions, enable encoder support.
2. Add encoder ID (e0) as the center label for encoder keys to support encoder mapping.
3. Added JSONs to src and v3.

QMK Pull Request

qmk/qmk_firmware#19844

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