[Usage collection] showcase collection APIs in an example plugin

[TinaHeiligers]

This issue is a follow up to #92193 for creating some example plugins using the collection APIs to showcase them and how they should be use.

The example plugin(s) need to demonstrate:

• client side ui_counters
• server side counters Provide a way to gather and store server side telemetry data #81645
• a custom collector
• application_usage (might be trickier to implement as it needs at least a minimal UI itself)
• ...others TBD

We need to decide what we want to display in the example.

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)