Add cli convert subcommand, from raw KLE to JSON (#6898)

Add cli convert subcommand, from raw KLE to JSON (#6898)

* Add initial pass at KLE convert

* Add cli log on convert

* Move kle2xy, add absolute filepath arg support

* Add overwrite flag, and context sensitive conversion

* Update docs/cli.md

* Fix converter.py typo

* Add convert unit test

* Rename to kle2qmk

* Rename subcommand

* Rename subcommand to kle2json

* Change tests to cover rename

* Rename in __init__.py

* Update CLI docs with new subcommand name

* Fix from suggestions in PR #6898

* Help with cases of case sensitivity

* Update cli.md

* Use angle brackets to indicate required option

* Make the output text more accurate