Move ResponseBody/List classes to service_client

ResponseBody/List classes are used as the return values of each
service client, so they are interfaces of service clients.
In addition, service_client depends on rest_client but now each
service client imports both rest_client and service_client.
This patch moves ResponseBody/List classes to service_client for
clean dependency and interfaces.

Change-Id: I080cedd0f0282d0abb5aa7a45edae8e178f36910
13 files changed