Use pathlib everywhere we can (#7872)

* Use pathlib everywhere we can

* Update lib/python/qmk/path.py

Co-Authored-By: Erovia <Erovia@users.noreply.github.com>

* Update lib/python/qmk/path.py

Co-Authored-By: Erovia <Erovia@users.noreply.github.com>

* Improvements based on @erovia's feedback

* rework qmk compile and qmk flash to use pathlib

* style

* Remove the subcommand_name argument from find_keyboard_keymap()

Co-authored-by: Erovia <Erovia@users.noreply.github.com>

lib/python/qmk/cli/list/keyboards.py

@@ -1,5 +1,6 @@
 """List the keyboards currently defined within QMK
 """
+# We avoid pathlib here because this is performance critical code.
 import os
 import glob