Separate out FAISS from requirements

[pseudotensor]

Fixes #181

================================================================================================================ short test summary info ================================================================================================================
FAILED tests/test_eval.py::test_eval1[False-4] - TypeError: GPTNeoXForCausalLM.__init__() got an unexpected keyword argument 'load_in_4bit'
FAILED tests/test_manual_test.py::test_chat_context - NotImplementedError: MANUAL TEST FOR NOW
FAILED tests/test_manual_test.py::test_upload_one_file - NotImplementedError: MANUAL TEST FOR NOW -- do and ask query of file
FAILED tests/test_manual_test.py::test_upload_multiple_file - NotImplementedError: MANUAL TEST FOR NOW -- do and ask query of files
FAILED tests/test_manual_test.py::test_upload_url - NotImplementedError: MANUAL TEST FOR NOW -- put in URL box https:/h2oai/h2ogpt/ (and ask what is h2ogpt?). Ensure can go to source links
FAILED tests/test_manual_test.py::test_upload_arxiv - NotImplementedError: MANUAL TEST FOR NOW -- paste in arxiv:1706.03762 and ask who wrote attention paper. Ensure can go to source links
FAILED tests/test_manual_test.py::test_upload_pasted_text - NotImplementedError: MANUAL TEST FOR NOW -- do and see test code for what to try
FAILED tests/test_manual_test.py::test_no_db_dirs - NotImplementedError: MANUAL TEST FOR NOW -- Remove db_dirs, ensure can still start up and use in MyData Mode.
FAILED tests/test_manual_test.py::test_upload_unsupported_file - NotImplementedError: MANUAL TEST FOR NOW -- e.g. json, ensure error correct and reasonable, no cascades
FAILED tests/test_manual_test.py::test_upload_to_UserData_and_MyData - NotImplementedError: MANUAL TEST FOR NOW Upload to each when enabled, ensure no failures
FAILED tests/test_manual_test.py::test_chat_control - NotImplementedError: MANUAL TEST FOR NOW save chat, select chats, clear chat, export, import, etc.
FAILED tests/test_manual_test.py::test_subset_only - NotImplementedError: MANUAL TEST FOR NOW UserData, Select Only for subset, then put in whisper.  Ensure get back only chunks of data with url links to data sources.
================================================================================ 12 failed, 48 passed, 25 skipped, 1 xfailed, 1 xpassed, 2 warnings in 911.47s (0:15:11)