Add lookup functions as wrappers for Samples codeservice #174
Description
A user may want to know what their options are for inputs to the samples function. For example: what are all the possible "activityMedia" inputs? This information is available from the Samples API codeservice: https://api.waterdata.usgs.gov/samples-data/codeservice/docs#/
However, we should make a set of functions that users can run that return the options in a nice, easy-to-understand format.