Make API easier, and add prompt_dict for custom control over prompt as example of new API parameter don't need to pass

[pseudotensor]

Gradio uses positional args, and so constantly breaking API when add new parameters to pass to server from client. Already made it so returned object is string of dict. Now made input string of dict too, i.e.:

from gradio_client import Client
client = Client(os.getenv('HOST', "http://localhost:7860"))

# string of dict for input
kwargs = dict(instruction_nochat='Who are you?')
res = client.predict(str(dict(kwargs)), api_name='/submit_nochat_api')

# string of dict for output
response = ast.literal_eval(res)['response']
assert 'I am h2oGPT' in response or "I'm h2oGPT" in response or 'I’m h2oGPT' in response

=========================== short test summary info ============================
FAILED tests/test_manual_test.py::test_chat_context - NotImplementedError: MA...
FAILED tests/test_manual_test.py::test_upload_one_file - NotImplementedError:...
FAILED tests/test_manual_test.py::test_upload_multiple_file - NotImplementedE...
FAILED tests/test_manual_test.py::test_upload_url - NotImplementedError: MANU...
FAILED tests/test_manual_test.py::test_upload_arxiv - NotImplementedError: MA...
FAILED tests/test_manual_test.py::test_upload_pasted_text - NotImplementedErr...
FAILED tests/test_manual_test.py::test_no_db_dirs - NotImplementedError: MANU...
FAILED tests/test_manual_test.py::test_upload_unsupported_file - NotImplement...
FAILED tests/test_manual_test.py::test_upload_to_UserData_and_MyData - NotImp...
FAILED tests/test_manual_test.py::test_chat_control - NotImplementedError: MA...
FAILED tests/test_manual_test.py::test_subset_only - NotImplementedError: MAN...
FAILED tests/test_manual_test.py::test_add_new_doc - NotImplementedError: MAN...
= 8 failed, 94 passed, 27 skipped, 1 xfailed, 1 xpassed, 9 warnings in 1638.52s (0:27:18) =