Add os-services extension support

Implement client bindings for Cinder os-services API extension, so
client would be able to list services, enable or disable particular
services.

Usage:
cinder service-list [--host <hostname>] [--binary <binary>]
cinder service-enable <hostname> <binary>
cinder service-disable <hostname> <binary>

This change is depended on following change at Cinder side
I7f3fa889294ca6caebdf46b8689345bcac1cdf54

Implements blueprint os-services-extension

Change-Id: I4a53fd545ed3b446441302d00a429168a996a34a
Merge "Add os-services extension support"