* Remove build dirs from docker image to keep the layers small
* Create setup_docker_prereqs script to prepare docker env
* Add documentation for required packages, drop colorlog and cython in first step of Dockerfile since it will be installed later on anyway. Drop libglib2.0-dev and libbluetooth-dev
* Also remove early install of colorlog and cython in Dockerfile.dev
* Re-add libglib2.0-dev and libbluetooth-dev for Bluetooth LE
