feat: add Player.Enumerable and Player.Count properties

[Banalny-Banan]

Description

Add two properties Player.Enumerable and Player.Count. First one is useful for optimizing LINQ calls to Player.List by avoiding creating new lists. Second one will promote not creating new lists for simple operations such as Player.List.Count - which currently first copies all players to a new list, not all people know to use Player.Dictionary.Count.

Does this PR introduce a breaking change?

No breaking changes

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentations

Submission checklist

• I have checked the project can be compiled
• I have tested my changes and it worked as expected

Patches (if there are any changes related to Harmony patches)

• I have checked no IL patching errors in the console

Other

• Still requires more testing