[dot-notation] add support for TS4.2's noPropertyAccessFromIndexSignature option

[bradzacher]

Repro

{
  "rules": {
    "@typescript-eslint/dot-notation": ["error"]
  }
}

interface GameSettings {
  // Known up-front properties
  speed: "fast" | "medium" | "slow";
  quality: "high" | "low";

  // Assume anything unknown to the interface
  // is a string.
  [key: string]: string;
}

declare const settings: GameSettings;

// good
settings.speed;
settings.quality;

// required to satisfy noPropertyAccessFromIndexSignature, but causes a dot-notation error
settings['username'];

We should add detection for the noPropertyAccessFromIndexSignature, and add logic so that it allows indexed access in the same cases.

This will allow you to use both this rule and the compiler option simultaneously.

[noullet]

Here is a slightly different situation:

I have the dot-notation rule as "warn" so I thought I could comply with TypeScript and live with the warning until it is properly supported, however lint --fix turns the indexed notation back into dot notation and breaks the TypeScript rule.