Add support for drop zones to k8s clusters

Current suggestion is to allow a syntax:

~plane::<plane>::<path>

e.g.,

myInput := DATASET('~plane::mydropzone::example.csv', rec, csv);
myInput2 := DATASET('~plane::myazure::regress::single::dg_csv._1_of_1', rec2, csv);

The plan is to also initialize the storage planes from the list of dropzones configured in the bare metal system, which will allow reading and writing to the drop zones using this syntax.