[CLI] `qmk docs` graceful shutdown on Ctrl+C (qmk#6989)

ARM split - detect USB to select master/slave (qmk#6424)

* Initial split refactor to allow usb master detection

* Add split USB detect docs

* Add SPLIT_USB_DETECT demo mode limitation

* fix rebase issues

* clang-format

[Docs] Fix missing link in readme (qmk#6958)

[Docs] CLI command to serve docs locally (qmk#6956)

* CLI command to serve docs locally

* Document it

* Default port

* Use `with` and subclass `SimpleHTTPRequestHandler` to set working dir

* Apply suggestions from code review

Co-Authored-By: skullydazed <[email protected]>

* Update docs/cli.md

[CLI] Add `qmk list_keyboards` (qmk#6927)

`list_keyboards` replicates the `make list-keyboards` by globbing for all paths
that include `rules.mk` and then removing the paths that include `keymaps`.

This basis of this cli command could be reused in the future as a util, but is
not done so here since this would be the only place that would use it currently

Resolves qmk#6911

Use `keymap` instead of `username` variable for `qmk new_keymap` (qmk…

…#6885)

Username is not defined and this causes `qmk new_keymap` to error.  This
appears to have originated from a partial update in
https://github.com/qmk/qmk_firmware/pull/6708/files#diff-d5208bcbc79aa428556a743b6ff41086.  This change completes the migration from `username` to `keymap`

removed deprecated option for Travis (qmk#6896)

ARM - Initial backlight support (qmk#6487)

* Move AVR backlight to own file, add borrowed ARM implementation

* Tiny fix for backlight custom logic

* Remove duplicate board from rebase

* Fix f303 onekey example

* clang-format

* clang-format

* Remove backlight keymap debug

* Initial pass of ARM backlight docs

* Initial pass of ARM backlight docs - resolve todos

* fix rules validation logic

* Add f072 warning

* Add f072 warning

* tidy up breathing in backlight keymap

* tidy up breathing in backlight keymap

* add missing break to backlight keymap

Fix qmk doctor 'bytes-like object is required' on linux

This fixes the following issue related to encoding on linux systems. Add
`universal_newlines=True` to subprocess.

<class 'TypeError'>
☒ a bytes-like object is required, not 'str'
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/milc.py", line 564, in __call__
    return self.__call__()
  File "/usr/local/lib/python3.7/site-packages/milc.py", line 569, in __call__
    return self._entrypoint(self)
  File "$HOME/qmk_firmware/lib/python/qmk/cli/doctor.py", line 56, in doctor
    for line in mm_check.stdout.split('\n'):
TypeError: a bytes-like object is required, not 'str'

Port drivers.txt changes from the Toolbox (qmk#6786)