Add Cmdlets to Get and Remove EngineEvents

[kilasuit]

Summary of the new feature / enhancement

As a user I want an easy way to Register, then Get, and the Remove engine events using builtin cmdlets

Proposed technical implementation details (optional)

Add the following Cmdlets
Get-EngineEvent
Remove-EngineEvent

[jborean93]

What benefit do you see this having over Get-Event, Remove-Event, Get-EventSubscriber? While there is a dedicated Register-EngineEvent I believe you are meant to use the generic *-Event cmdlets to manage events that are subscribed from various providers. You can even publicly extend your own event source like I've done in PSEtw.