Updates to lalinference pipeline to allow containerization

This modifies the lalinference_pipe and associated scripts/modules to allow lalinference to be run in a singularity container. The aim is to eventually enable running on the OpenScienceGrid, but this is not yet working due to issues with Singularity being installed in a reliable location. It also cleans up the logic in lalinference_pipe that allows the user to specify multiple engines, waveforms etc.