Deprecate EntityList.FindFirst/FindAll

### I am planning on implementing this myself

No

### Describe your request

These methods are a beginner trap that can end up severely affecting performance in large rooms, especially as part of hooks.
Since it's possible to dynamically add types to the Tracker now, that solution should be preferred.

Potential obsoletion message:
`[Obsolete("O(n) operation, use Scene.Tracker.GetEntity instead. (requires [Tracked] attribute on T. If T is not a type you own and it does not have the [Tracked] attribute, use Tracker.AddTypeToTracker on that type first.)")]`

### Additional context

_No response_