Ability to set EventThreshold at Node and DeliveryMethod level

Why is it useful?

It provides ability to just publish only SHP or PICK Inventory Events (either Node or Dg level). Because in many of the IV implementations, where there is no separate Availability for SHP and PICK. In such cases, currently, the recommendation from IBM is to just let the consumer system to ignore the Inventory Event message (e.g DeliveryMethod=PICK) that is not required. But this is not a clean and efficient integration.

Note: We cant use fulfillmentOverrides to disable a specific DeliveryMethod (lets say for DeliveryMethod=PICK) to address this use case. Because eventhough it would suppress the Inventory Event messages for a given Del method PICK, the node/network availability API will also return 0 availability for the Del method=PICK, unless we explicitly set considerFulfillmentOptions=false. 

Who would benefit from?

Customers who do not have requirements to maintain separate inventory availability for SHP and PICK in the store front cache. And just use single availability (either node or network) and take up SHP and PICK orders and fulfill.

How should it work?

- Node level availability should still be calculated and maintained in IV for SHP , PICK by default. So that OMS to IV , OOB inventory calls (node or dg level during the findInventory or sourcing) would work as it is for both SHP and PICK items.

- An API to update Event Threshold configuration at Node and DeliveryMethod level (e.g as eventThreshold=NONE) so that the existing Inventory Events publish honor this configuration as well.

  - e.g if Node + Delivery Method level EventThreshold exist's honor at this level, else honor the Node level Event Threshold.