GH60 additions

[dunk2k]

Description

For both gh60 boards in v3 directory, add:

• ABNT2 split Right Shift (1u-1.75u)
  • amend Right Shift in labels to accommodate
• Infinity Hacker and True/6u HHKB bottom row layouts
  • amend bottom row labels to accommodate

QMK Pull Request

This PR does not add a new keyboard

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

[dunk2k]

superseded by #2267