Consumption Usage Price Override - Unituitive Implementation

[shaun-forgie]

When overriding a consumable usage price you need to include all the usage types for the plan. It means we have to include all prices for all usages defined in the plan. Where a plan contains twenty or more types of usage this become overly difficult and unintuitive to do.

Our recommendation is to only include the usage types that are actually being changed from the default values in the price override call.

We understand from the existing implementation that capacity based usage types do not support price overrides. It would also be good if we could override those as well. See #2010