add simulation option to only generate the parameter listing only

[MarshallAsch]

Instead of only being able to run all the simulations it would be beneficial if all of the parameter combinations can be generated to be run separately as batches.

1. Call campaignmanager.get_missing_simulations()
2. split that listing into multiple chunks
3. save each listing to its own file

running:

1. take in the name of the file that contains the parameters
2. run the missing simulations

results merge