[IOT-955] To separate of pairing BT

[IOT-955] To separate of pairing BT

If there were a number of BT devices near the user device,
user device will try to request pairing key exchange regardless
BT device owner.

it can cause very serious user experience problem.
so. i have added BT pairing from discovery procedure.
then the iotivity tries to find resources from
already paired BT devices provided each platform.

Change-Id: I8adee751c8e66e87a54ccc1b27ec0800c1c1edb3
Signed-off-by: jihwan.seo <jihwan.seo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/5093
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>