refactor players into a map

[nstringham]

the players array is hard to use because indexof is O(n) we should replace it with a map from uid to player because this is faster more readable and works in firestore function

Task List:

• Update the players in firestore
• Update all locations where players is being used
• All Client Files
• All Functions Files
• All Firestore Rules

Acceptance criteria:

• players should be {[uid: string]: Player} instead of Player[]
• everything else should still work