Move security identity out of CAEndpoint_t and OCDevAddr.

Move security identity out of CAEndpoint_t and OCDevAddr.

Move security identity to CAInfo_t.
Propagate security to OCClientResponse for application.

Change-Id: I535577bedf0ed4f46a97249add56aec6928d2d84
Signed-off-by: John Light <john.j.light@intel.com>
Signed-off-by: Sakthivel Samidurai <sakthivel.samidurai@intel.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/2144
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>