python: split Makefile into smaller files

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>
python: remove explicit compile rule; works without it

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>
python: remove some explicit rules in favor of using make/configure vars

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>