make sure fields param works in all routes

[sckott]

No description provided.

[sckott]

@ojalaquellueva looked at this - right now there are a few routes that can accept user input fields param with what fields they want back - but i've been followingn the SQL used in the R pkg, and they've hardcoded the select fields (the fields to return)

I could code the routes to just accept any fields, but that would be changing behavior from what the R API was doing - up to you all

some explanation in docs for the fields param https://ropensci.github.io/bienapidocs/#sometimes-available