Regroup all 'Exclusive' keyboards in one subdirectory

[masterzen]

Description

To reduce clutter in the keyboards/ directory, this patch moves all keyboard definitions for 'Exclusive' boards to its own subdirectory.

Types of changes

• Core
• Bugfix
• New Feature
• Enhancement/Optimization
• Keyboard (addition or update)
• Keymap/Layout/Userspace (addition or update)
• Documentation

Issues Fixed or Closed by this PR

• None, @mechmerlin suggested this change :)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document. (https://docs.qmk.fm/#/contributing)
• 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).

[masterzen]

I'm not sure why make exclusive:all doesn't work. Note it doesn't seem to work for any high level keyboard directory (for instance sentraq or kbdfans).

[drashna]

@masterzen That's normal. Because there are no keyboard files in the folder, there is nothing to compile there.

However, the Travis CI script handles this just fine.

Speaking of which, it looks like the Travis CI error is due to a size issue with one of the layouts. THis is fine, as all the default keymaps appear to compile just fine.

[drashna]

Thanks!