Improve "Modify And" experiment commands

[mattseddon]

DVC has recently released a Hydra integration which enables grid search functionality. There are a couple of tasks here:

• [ ] Add the ability to submit a range/list for selected params depending on whether they are numeric/string (if possible).
• [ ] Run "apply experiment" at the start of all of the "modify and" commands (so that the data is correct before starting the experiment).