[MSAL] Adopt Broker flow in Microsoft Auth provider via MSAL-node

[TylerLeonhardt]

Docs here:
https://github.com/AzureAD/microsoft-authentication-library-for-js/tree/dev/extensions/msal-node-extensions#usage---brokering

I talked to @deepak1556 about this one and the design we want to go with is having this native node module (@azure/msal-node-extensions) brought in to Core and have a worker/process that could process these requests. This way the ExtHost is not polluted with this native node module.

So the Microsoft Authentication extension:

1. will talk to the Core window
2. (optional) Core window talks to the Main Process
3. and the Core window or Main process talks to this other process/worker

This could be API.. or maybe some other mechanism. API probably makes the most sense. Maybe a require interceptor if those still exist in a post-ESM world?