Add VIA support for Keychron V6

[KeychronMacro]

As the title.

Description

• Add VIA JSONs for Keychron V6.

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#19498

Checklist

• The VIA support for this keyboard is in QMK master already (MANDATORY)
• The VIA definition follows the guide here: https://caniusevia.com/docs/layouts
• 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

[yiancar]

Cheers thanks:)