Improve help in command-line utility

Show list of drivers, available actions, services
and networks supported by drivers.

Change-Id: Ic7c038933a9e44464198abcf072f1512dcf6ffd3

os_faults/api/base_driver.py

@@ -14,7 +14,12 @@
 
 class BaseDriver(object):
     NAME = 'base'
+    DESCRIPTION = 'base driver'
 
     @classmethod
     def get_driver_name(cls):
         return cls.NAME
+
+    @classmethod
+    def get_driver_description(cls):
+        return cls.DESCRIPTION