Adds a link to proxy server configuration reference
Adds a link to proxy server configuration reference

Adds a link to information concerning local "write_affinity" and
 "write_affinity_node_count" as well as other proxy server
 settings and configurations.

Change-Id: If4fd46ee443b57f09f179377970646f19b83f0e4
Closes-Bug: #1192657

openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,Akasurde/openstack-manuals,potsmaster/openstack-manuals,saeki-masaki/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,kairoaraujo/openstack-manuals,saeki-masaki/openstack-manuals,gongysh2004/openstack-manual,AlekhyaMallina-Vedams/openstack-manuals,gongysh2004/openstack-manual,openstack/openstack-manuals,potsmaster/openstack-manuals,kairoaraujo/openstack-manuals,Akasurde/openstack-manuals