test: ability to accept gzip compressed files

[hubert-rutkowski85]

The PR adds tests:

• unit tests comparing response between gzipped and not-gzipped files, for different content types, also for non-set ungzipped content type, and for single and multiple files in various combinations.
• simple smoke tests

To test only new unit tests:

PYTHONPATH=. python -m pytest -v test_general/api/test_gzip.py --disable-warnings

[hubert-rutkowski85]

I know I need to update the requirements/ test.txt and base.txt with correct packages, but had some pip-compile issues not seeing venv and couldn't finish it today, but it's detail and don't want to wait with review request. EDIT: the failing test is failing for me also on main, so it's rather not caused by my changes. EDIT2: pip-compile is fixed, that test passes, but a new one fails (maybe it's caused by some library update, works on localhost):

FAILED test_general/api/test_app.py::test_languages_and_ocr_languages_raises_error - Failed: DID NOT RAISE <class 'ValueError'>

EDIT3: oh noes, it passess on main https://github.com/Unstructured-IO/unstructured-api/actions/runs/8144148394/job/22257691407 , but it also fails when I include pip-compile requirements changes. So it makes sense some dependency changed. Now need to bisect to find the One...