Support EventBridge ListPartnerEventSources & PutPartnerEvents

**@Slipdexic**

It would be great to use this tool to show a list of AWS EventBridge Partner event sources
ListPartnerEventSources() and to be able to post data to using PutPartnerEvents()

The PutPartnerEvents() is the same as PutEvents() it just takes an extra parameter
"EventBusName": "string" which is the ARN to the customers EventBus

This feature would only apply to AWS EventBridge Partners not to AWS Customers
https://docs.aws.amazon.com/eventbridge/latest/APIReference/API_ListPartnerEventSources.html
https://docs.aws.amazon.com/eventbridge/latest/APIReference/API_PutPartnerEvents.html

I was looking at the source code , to see if this is something I can add, It seems relatively simple.

One of the ideas I had was a may be add a startup param for "partner-mode" when this mode is active Instead of displaying the getEventBuses() switch that to display the "ListPartnerEventSources"
as your not likely interested in your own buses more injecting into customer buses
so if on the Press "i" on DASHBOARD_FOCUS_INDEX.EVENT_BRIDGE_TREE
still use the same eventInjectionModal screen as it already has all of the required params include the extra "EventBusName" and having the main.injectEvent()
call PutPartnerEvents() instead of PutEvents()

Darryl