Expand usage of GET calls in waterdata module

[ehinman]

From Water Data APIs product owner:

You can now query for multiple parameter codes, statistic IDs, monitoring location IDs, etc! Separate your multiple values using commas. This should be equivalent to running a CQL "in" for these fields.
https://api.waterdata.usgs.gov/ogcapi/v0/collections/daily/items?monitoring_location_id=USGS-01435000&parameter_code=00060,00010&time=P1D

These fields are enabled field-by-field for each endpoint independently. If a field supports multiple arguments, you'll see this in its documentation on Swagger (and presumably soon in dataRetrieval!):

Split parameters are enabled for this field, so you can supply multiple values separated by commas

Currently, the waterdata module uses a POST call with CQL if more than one input value is supplied. This is no longer required.