Add keyboard: Xtrfy K4 TKL RGB, ISO only, no RGB support

[humanplayer2]

Adds support for Xtrfy K4 TKL RGB board. ISO only, no RGB support.

I have been unable to get rid of all RGB code to make a clean plain version.

[humanplayer2]

@dexter93 has now helped me clean out the RGB LED things.

[humanplayer2]

@dexter93 suggested this should be based on keychron/k8 from sn32_develop instead of sn32_master. This has now been done.

[github-actions]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
For maintainers: Please label with bug, awaiting review, breaking_change, in progress, or on hold to prevent the issue from being re-flagged.

[dexter93]

/nostale

[github-actions]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
For maintainers: Please label with bug, awaiting review, breaking_change, in progress, or on hold to prevent the issue from being re-flagged.

[humanplayer2]

@dexter93 , I think I made the changes you requested.