Extend submitter to HTCondor

[anmalara]

Current situation and requested solution

Submitter works for slurm only, should extend it to HTCondor.

To be done after

• Nothing

To be done before

• Nothing

Steps

• Create needed files for HTCondor
• Move to full python scripts also for slurm, e.g. don't specify anything in sh script. Wrap up into class that interfaces with the sh script.
• Make a class to handle scheduler specifics
• Added documentation

[anmalara]

Partially solved in #49. Need to think if it's worth moving the slurm part to python-only.