Added Leaderboard for WebGL Build using Firebase

Adding a database to a WebGL build of a game is more difficult than I thought. 

At of the time of writing this, Firebase hasn't released any direct tools to support their product with Unity WebGL. Thankfully, https://www.youtube.com/@uNicoDev has built a tool specifically for this! https://github.com/rotolonico/FirebaseWebGL.

Soooo, with that tool and a lot of stumbles on my part, this update ended quite nicely.