[Other] Hub feature: add model hub management for fastdeploy (#453)

* add hub tool for fastdeploy

* fix format

* refactor code

* remove EasyDict

Co-authored-by: Jason <jiangjiajun@baidu.com>

python/fastdeploy/utils/hub_env.py

@@ -0,0 +1,54 @@
+# Copyright (c) 2022  PaddlePaddle Authors. All Rights Reserved.
+#
+# 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.
+'''
+This module is used to store environmental variables for fastdeploy model hub.
+
+FASTDEPLOY_HUB_HOME              -->  the root directory for storing fastdeploy model hub related data. Default to ~/.fastdeploy. Users can change the
+├                          default value through the FASTDEPLOY_HUB_HOME environment variable.
+├── MODEL_HOME       -->   Store the downloaded fastdeploy models.
+├── CONF_HOME        -->   Store the default configuration files.
+'''
+
+import os
+
+
+def _get_user_home():
+    return os.path.expanduser('~')
+
+
+def _get_hub_home():
+    if 'FASTDEPLOY_HUB_HOME' in os.environ:
+        home_path = os.environ['FASTDEPLOY_HUB_HOME']
+        if os.path.exists(home_path):
+            if os.path.isdir(home_path):
+                return home_path
+            else:
+                raise RuntimeError(
+                    'The environment variable FASTDEPLOY_HUB_HOME {} is not a directory.'.
+                    format(home_path))
+        else:
+            return home_path
+    return os.path.join(_get_user_home(), '.fastdeploy')
+
+
+def _get_sub_home(directory):
+    home = os.path.join(_get_hub_home(), directory)
+    os.makedirs(home, exist_ok=True)
+    return home
+
+
+USER_HOME = _get_user_home()
+HUB_HOME = _get_hub_home()
+MODEL_HOME = _get_sub_home('models')
+CONF_HOME = _get_sub_home('conf')