Address #52 almost entirely - target upstream builds of CircuitPython and simply copy (rsync) KMK source, a basic main.py, and the user's keymap to the CIRCUITPY drive

.gitmodules

@@ -1,7 +1,3 @@
-[submodule "circuitpython"]
-	path = vendor/circuitpython
-	url = https://github.com/kmkfw/circuitpython.git
-	ignore = dirty
 [submodule "upy-lib"]
 	path = vendor/upy-lib
 	url = https://github.com/kmkfw/micropython-lib.git