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.

common/classes.py

@@ -0,0 +1,48 @@
+from decouple import Config, RepositoryEnv, UndefinedValueError
+from etcd3_wrapper import EtcdEntry
+
+
+class EnvironmentVariables:
+    def __init__(self, env_file):
+        try:
+            env_config = Config(RepositoryEnv(env_file))
+        except FileNotFoundError:
+            print("{} does not exists".format(env_file))
+            exit(1)
+        else:
+            self.config = env_config
+
+    def get(self, *args, **kwargs):
+        """Return value of var from env_vars"""
+        try:
+            value = self.config.get(*args, **kwargs)
+        except UndefinedValueError as e:
+            print(e)
+            exit(1)
+        else:
+            return value
+
+
+class SpecificEtcdEntryBase:
+    def __init__(self, e: EtcdEntry):
+        self.key = e.key
+
+        for k in e.value.keys():
+            self.__setattr__(k, e.value[k])
+
+    def original_keys(self):
+        r = dict(self.__dict__)
+        if "key" in r:
+            del r["key"]
+        return r
+
+    @property
+    def value(self):
+        return self.original_keys()
+
+    @value.setter
+    def value(self, v):
+        self.__dict__ = v
+
+    def __repr__(self):
+        return str(dict(self.__dict__))