Implement versioning for events

[KevinSnyderCodes]

There are now two versions of events out there:

• v1: only alive, playernames, and playerKill
• v2: new events from 08-21 beta build

Event consumers should know which version of the events are being provided so they can act appropriately. For example, we wouldn't want to show anything related to berries or snail in a post-game scoreboard if the game doesn't provide those events.

Questions to answer:

• Are events backwards compatible between v1 and v2?
  • playerKill is the only event that needs to be checked here
• Should the event version detection be automatic or manual?
  • We can assume v1 until a v2 event appears. The downside to this is that versioning responsibility is deferred to the consumer, and they will need to implement fancy switching when that v2 event rolls in. If we manually set a fixed version at the beginning, the consumers have less work to do, but then we need to make sure the version is always set correctly.