Add remote vs local FAQ for callbacks
Add remote vs local FAQ for callbacks

Change-Id: I4993c9a0101fab23d04852f753ea6e9b74ff0712

sebrandon1/neutron,mahak/neutron,openstack/neutron,igor-toga/local-snat,mahak/neutron,huntxu/neutron,bigswitch/neutron,sebrandon1/neutron,cloudbase/neutron,wolverineav/neutron,eayunstack/neutron,MaximNevrov/neutron,MaximNevrov/neutron,noironetworks/neutron,klmitch/neutron,huntxu/neutron,wolverineav/neutron,eayunstack/neutron,cloudbase/neutron,mahak/neutron,openstack/neutron,openstack/neutron,klmitch/neutron,bigswitch/neutron,igor-toga/local-snat,noironetworks/neutron