Improve naming conventions in a future major release

[Cervator]

I think we should formalize naming for a few major class types. At present we have some inconsistencies like BeforeDeactivateComponent which is actually an Event and should probably be named BeforeDeactivateComponentEvent

We could probably write Checkstyle rules to help enforce this. The types I have in mind:

• Systems should end in System
• Components should end in Component
• Events should end in Event
• Maybe something about Actions? They may be too ambiguous at present to narrow down. Are they supposed to be sort of like a System version of a functional interface - they only do one thing? Should they be an allowed exception to the System naming or does that just complicate things?

If there are no objections I think we should move ahead with marking style violations then @deprecate poorly named classes as we come across them, much like fixing style violations in general (if you're working in an area keep an eye out). Offer a better named replacement class, potentially with a new handler method somewhere with the old one just calling the new one, and let modules migrate to the new naming over time. Then delete the outdated version come next major release. Unless the deprecation was too recent.

Candidates:

• BeforeDeactivateComponent to BeforeDeactivateComponentEvent - widely used across modules
• OnActivatedComponent to OnActivatedComponentEvent