Added exact_match to list_folders

[srivarra]

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What is the purpose of this PR?

This PR closes #360. It adds an exact_match function parameter to the list_folders function. In addition it adds specific tests for
the case where exact_match is set to True.

How did you implement your changes

1. The same case from list_files was used.
2. Instances of using .sort() within assert statements were replaced with sorted(), as .sort() returns None.

Remaining issues

There could be more instances of using asserts with .sort()
instead of sorted().

For example:

a = [6,5,4,3]

assert a.sort() == [3,4,5,6]

Would not pass as a.sort() returns None.

However:

a = [6,5,4,3]

assert sorted(a) == [3,4,5,6]

Would pass as sorted() returns the sorted iterable.

[ngreenwald]

The build is failing due to the linter being unhappy with your code. When you run the tests locally, make sure to add the --pycodestyle flag to pytest so that you'll see the same errors as github. You can google pep8 style guide to read up best practices

[alex-l-kong]

Just a couple testing comments.

[alex-l-kong]

Looks good, liking the new test_list_folders structure with separate sections for exact_match = False and exact_match = True.

[ngreenwald]

Syntax looks nice, see comments below