Add kt60-MU PCB

[key10iq]

Description

kt60-MU is a 60% PCB supporting QMK and VIA, compatible with many 60% keyboards

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout (addition or update)
• Documentation

Issues Fixed or Closed by This PR

• Added new keyboard - keyten/kt60_mu

Checklist

• My code follows the code style of this project: C, Python
• I have read the PR Checklist document and have made the appropriate changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[key10iq]

To anticipate the question, this PCB really needs a backlight definition, despite the fact that it only has two LEDs (one of which is defined as a Caps Lock indicator), lol

[key10iq]

@dunk2k sorry for ping, but...

[dunk2k]

@dunk2k sorry for ping, but...

Hi @key10iq,
I'm not a QMK Collaborator so unfortunately my approval wouldn't count toward this PR being merged. I'm able to give this PR another look over and subsequent approval if it would be meaningful to you?

[sigprof]

Some minor nits (trailing spaces and a trailing comma which would make the file not a valid JSON).

[key10iq]

@dunk2k sorry for ping, but...

Hi @key10iq, I'm not a QMK Collaborator so unfortunately my approval wouldn't count toward this PR being merged. I'm able to give this PR another look over and subsequent approval if it would be meaningful to you?

Oh, sorry, for some reason I always thought you were a QMK Collaborator, haha. In general, I'll be glad if you look over my PR again!