Add decorators for determining keyboard and keymap based on current directory (#8191)

* Use pathlib everywhere we can

* 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()

* add experimental decorators

* Create decorators for finding keyboard and keymap based on current directory.

Decorators were inspired by @Erovia's brilliant work on the proof of concept.

lib/python/qmk/path.py

@@ -65,7 +65,7 @@ def normpath(path):
     path = Path(path)
 
     if path.is_absolute():
-        return Path(path)
+        return path
 
     return Path(os.environ['ORIG_CWD']) / path