Remove ucloud_common and put its files under ucloud.common subpackage.

Remove individual config.py used by every component and put them into single config.py ucloud/config.py
Use /etc/ucloud/ucloud.conf for Environment Variables
Refactoring and a lot of it
Make ucloud repo a package and different components of ucloud a subpackage for avoiding code duplication.
Improved logging.

scheduler/tests/test_dead_host_mechanism.py

@@ -1,24 +1,18 @@
-import unittest
 import sys
-import json
-import multiprocessing
-import time
-
+import unittest
 from datetime import datetime
 from os.path import dirname
+
 BASE_DIR = dirname(dirname(__file__))
 sys.path.insert(0, BASE_DIR)
 
 from main import (
-    accumulated_specs,
-    remaining_resources,
-    VmPool,
     dead_host_detection,
     dead_host_mitigation,
-    main,
     config
 )
 
+
 class TestDeadHostMechanism(unittest.TestCase):
     def setUp(self):
         self.client = config.etcd_client