Modified RCSSeparateResponse to send the response built by interface handlers.

Modified RCSSeparateResponse to send the response built by interface handlers.

RCSResourceObject has interface handlers in order to build proper responses by the interfaces of the requests.
Separate response should use them to build the response.

Change-Id: Ic2b9af279acbecf025a06b493347d6d5cbdea20c
Signed-off-by: coderhyme <jhyo.kim@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/5285
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Uze Choi <uzchoi@samsung.com>