Create CALDB containers

Currently `docker-heasoft` containers use the default CALDB interface, which means it uses NASA's FTP to get calibration data.

It is not clear to me though is providing the CALDB volume-images is the best solution (they can be quite large ~5GB); maybe providing a recipe for creating and plugging the CALDB image into the heasoft container is also a good, inexpensive solution.
