reduce iterations in query and list by refactoring to use a transducer pattern

[TillaTheHun0]

We iterate over list of documents in this adapter quite a bit, and we usually do so sequentially -- "filter out these docs", "omit this field on each doc", "add this field". Each of these actions iterates through the array, which is fine for small lists of documents but could potentially have real impacts on performance with large lists of docs.

Instead, we should leverage transduce to reduce the number of times we iterate through a list to a single iteration, performing all transformations during that single iteration.

I should be able to refactor the code, and then run the unit tests to ensure nothing is broken

- [ ] #38

• queryDocuments
• listDocuments

[TillaTheHun0]

I'll also use this opportunity to beef up the test coverage on this adapter. I'm noticing now that it's not where i'd like it to be.

[twilson63]

Nice! Great work!

[TillaTheHun0]

bulkDocuments has a lot of moving parts, so i'd like to do that separately. Covered in #38