[IOT-1785] Roles: /oic/sec/acl2 resource and policy changes

[IOT-1785] Roles: /oic/sec/acl2 resource and policy changes

This also starts writing the ACL resource to persistent storage
in the ACL2 format, but either the ACL or ACL2 format can still
be read.

Change-Id: I0a324aec906aef23e3681fc2401b44fcab205618
Signed-off-by: Kevin Kane <kkane@microsoft.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/17785
Reviewed-by: Alex Kelley <alexke@microsoft.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
Reviewed-by: Greg Zaverucha <gregz@microsoft.com>