LSF Manager updates

[priyavadan]

Currently when a command is submitted to the LSF, origen still executes the "source source_setup" script see here.

I believe this is an archaic way of invoking origen and we have since evolved to a point where we will not need this going forward.

I will submit a PR for this issue. The plan is to use the Site Config variables to define a "lsf_command_prefix" so that existing functionality is preserved.

I can forsee that this might be a breaking change and jobs might not be submitted to the LSF if someone is still using the old way of making Origen available within the organization and if the site_config parameter isn't defined, so will run some checks and confirm.