Allow collections kept by SimpleResourceDefinition.Parameters to be appended

The Parameters object is meant to be built with a builder and then passed into SimpleResourceDefinition constructors. It is useful for scenarios where RD's are based on subclassing to let the superclass add items to the passed in set of access constraints, capabilities and incorporating capabilities instead of forcing the subclass constructor itself to manually read existing values, create new collections with added values, and then re-set the overall collection.