The MaintenancePlan will provide some context for the RRS records so we
can effectively enable RRS functionality only on certain layers where we
want it. You can also consider the maintenance of multiple layers
together under a single plan if desired.
Here we add just the MaintenancePlan and the corresponding migration;
a non-null link from the Release requires a separate migration and thus
that will be done in a separate commit.
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
