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_basics.py

@@ -1,13 +1,10 @@
-import unittest
-import sys
 import json
 import multiprocessing
-import time
-
+import sys
+import unittest
 from datetime import datetime
 from os.path import dirname
 
-
 BASE_DIR = dirname(dirname(__file__))
 sys.path.insert(0, BASE_DIR)
 
@@ -15,13 +12,12 @@ from main import (
     accumulated_specs,
     remaining_resources,
     VmPool,
-    dead_host_detection,
-    dead_host_mitigation,
     main,
 )
 
 from config import etcd_client
 
+
 class TestFunctions(unittest.TestCase):
     @classmethod
     def setUpClass(cls):