Created new_keymap.py, python version of new_keymap.sh (#6066)

Created new_keymap.py, python version of new_keymap.sh (#6066)

* Created python version of new_keymap.sh: new_keymap.py

* Updated usage message

* Updated new_keymap.py to use python3.5+ syntax & be more similar to new_keyboard.sh

* Updated complete message

* Updated usage in argparser and removed incorrect usage_message

* Reverted the fstrings back to strings that use .format() & updated docstring convention

* Added helper to recursively cd .. until at qmk_firmware root directory

* Revert "Added helper to recursively cd .. until at qmk_firmware root directory"

This reverts commit 61a0ff3b25f91901287bec8d58eb51a1f126e2ad.

* Updated new_keymap.py to use printf-style format strings

* First draft lib/python/qmk/cli/new/keymap.py with milc

* Removed shebang & syspath appending lines

* Added optional args & resolved some cr comemnts

* Added a docstring and updated strings