check index of Q series to allow for datetime index

Allowing the user to send a series of pumping with a datetime index might be useful.

Testing the type of index and converting to integer days would help simplify the generation of the series for the user and eliminate a step in their process - see the example notebook on the Well Class for the current process.

Start with the example notebook and the Well Class referenced in the issue, then trace how a pumping series index is currently handled. The work is done when a series with a datetime index is accepted and its generation matches the existing integer-day behavior, eliminating the user's conversion step.

Written by the indexing model from the issue text.