Remove unnecessary define and files for SSL

Remove unnecessary define and files for SSL

1) Removed X.509 build option because it is enabled by default
2) Deleted DTLS and TLS adapter files because thay are included in SSL

Change-Id: I078c5b0c912801f17fa858d6fdd2abe39feed9f8
Signed-off-by: Dmitriy Zhuravlev <d.zhuravlev@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/13115
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Kevin Kane <kkane@microsoft.com>
Reviewed-by: Ashwini  Kumar <k.ashwini@samsung.com>
Reviewed-by: Randeep Singh <randeep.s@samsung.com>