Update defaults + add production_date to schema

[amondal2]

-- Removes required parameters so that they don't need to be specified from the GUI; the underlying Python code should handle the case where no inputs are provided

-- Adding a production_date input field

-- Updating tests

[amondal2]

@zsusswein Probably. We can do something like this? https://stackoverflow.com/questions/27587127/how-to-convert-datetime-date-today-to-utc-time