DocuBleach - Reorganise test files

[Patterbear]

The test files for both test suites are currently all together in the 'test_files' directory.

This is a problem for two reasons:

1. Module setup/teardown means that, for any test suite, every single file, including those that are not used in the test suite, are backed up and restored. This is inefficient and will only become more inefficient as more test suites are added (like the upcoming BFF one).

2. It's just not as organised as it could be.

To remedy this, I plan to create subfolders for each test suite's files, and then amend the paths within the suites to point to the subfolders instead.