Placed OC random functionality at common place for RI and CA to use

Placed  OC random functionality at common place for RI and CA to use

Moved OC random implementation to c_common folder to make it available for CA as well. As Seed Random should be called at common place for RI and CA.

Change-Id: I0a7cd674b9c4212b3a1d1e382aa1f455bec1a6d2
Signed-off-by: koushik.girijala <g.koushik@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/4101
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>
Signed-off-by: koushik.girijala <g.koushik@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/4455