Cleanup of Docker code based on lessons learned from trying to dockerize
an application. See also gdp-if/mqtt-gdp-gateway.
Some versions of Linux require echo -e to expand "\033", but other
systems don't know about -e. Change the "\033"s with literal escapes.
Add documentation about required packages (arguably these should just be
Add administrative scripts:
adm/gdp-setup.sh --- sets up the environment for GDP, including
getting all the packages needed.
adm/gdp-debbuild.sh --- builds a debian package for the library
(to be augmented later to install the rest of the code).