Parameter list and descriptions for mo.convert_model() method in docstring (#16459)

* Added convert_model() params docs.

* Added auto-generating of most cli params.

* Added auto-generating of cli params.

* Small correction.

* Removed wrong change.

* Corrected default values.

* Fixed errors, added tests.

* Small correction.

* Corrected params descriptions, moved cli specific params to separate file.

* Moved params specifics to utils/help.py.

tests/layer_tests/mo_python_api_tests/mo_convert_help.py

@@ -0,0 +1,7 @@
+# Copyright (C) 2018-2023 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+from openvino.tools.mo import convert_model
+
+if __name__ == "__main__":
+    convert_model(help=True)

tests/layer_tests/mo_python_api_tests/test_mo_help.py

@@ -0,0 +1,39 @@
+# Copyright (C) 2018-2023 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+
+import os
+import sys
+import unittest
+from openvino.tools.mo import mo
+from openvino.tools.mo.utils.cli_parser import get_mo_convert_params
+from pathlib import Path
+
+from common.utils.common_utils import shell
+
+
+class TestSubprocessMoConvert(unittest.TestCase):
+    def test_mo_convert(self):
+        mo_convert_params = get_mo_convert_params()
+
+        # Test cli tool help
+        mo_path = Path(mo.__file__).parent
+        mo_runner = mo_path.joinpath('main.py').as_posix()
+        params = [sys.executable, mo_runner, "--help"]
+        _, mo_output, _ = shell(params)
+
+        # We don't expect PyTorch specific parameters to be in help message of the MO tool.
+        for group in mo_convert_params:
+            if group == 'Pytorch-specific parameters:':
+                continue
+            for param_name in group:
+                assert param_name in mo_output
+
+        # Test Python API help
+        mo_help_file = os.path.join(os.path.dirname(__file__), "mo_convert_help.py")
+        params = [sys.executable, mo_help_file]
+        _, mo_output, _ = shell(params)
+
+        for group in mo_convert_params:
+            for param_name in group:
+                assert param_name in mo_output