CI: Add pre-commit for esp-idf project.

add tools/ci/python_packages/idf_ci.py for some util functions used in
ci and needs multi-os solution

tools/ci/idf_ci_utils.py

@@ -0,0 +1,43 @@
+# internal use only for CI
+# some CI related util functions
+#
+# Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+import logging
+import os
+import subprocess
+
+IDF_PATH = os.getenv('IDF_PATH', os.getcwd())
+
+
+def get_submodule_dirs():  # type: () -> list
+    """
+    To avoid issue could be introduced by multi-os or additional dependency,
+    we use python and git to get this output
+    :return: List of submodule dirs
+    """
+    dirs = []
+    try:
+        lines = subprocess.check_output(
+            ['git', 'config', '--file', os.path.realpath(os.path.join(IDF_PATH, '.gitmodules')),
+             '--get-regexp', 'path']).decode('utf8').strip().split('\n')
+        for line in lines:
+            _, path = line.split(' ')
+            dirs.append(path)
+    except Exception as e:
+        logging.warning(str(e))
+
+    return dirs