gluster: Tables, SPs and DAOs for gluster services

These tables will store information about gluster related services
running on servers of gluster storage clusters.

gluster_service_types : Type of the service e.g. gluster-swift
gluster_services : Service type to services mapping
  (gluster-swift-proxy, gluster-swift-container, etc)
gluster_cluster_services : Cluster to service types mapping
gluster_server_services : Server to services mapping

In this process, renamed the class ServiceInfo to GlusterServerService

Change-Id: I1ded8d39203009bc66974e136c41b5de180ffbff
Signed-off-by: Shireesh Anjal <sanjal@redhat.com>