Add TypeScript and Jest config

[whymarrh]

This PR adds a ESLint config for TypeScript and Jest. These can be used by extending them in client projects:^[1]

module.exports = {
   root: true,
   extends: [
     '@metamask/eslint-config',
     '@metamask/eslint-config/config/jest',
     '@metamask/eslint-config/config/typescript',
   ],
 };

You can see an example of this in action over at MetaMask/safe-event-emitter#1.

Important notes:

1. I've simply inlined the MetaMask extension config as the default/base set of rules. In the future we can add all of the core ESLint rules there as the default set of rules (i.e. config/index.js) and disable what we need to. I've created (Explicitly set all of the core ESLint rules #1) to track that work.
2. I've left out any and all TypeScript rules that require type information. I've left them out because they're "slow" and I don't quite know (yet) how they behave with a project that doesn't compile. I've created (Add settings for all of the TypeScript rules that require type information #2) to track the addition of those rules.

[whymarrh]

@Gudahtt @rekmarks my hope here is that we:

1. Publish the first version of the base config here and introduce that into the extension
2. Agree that enabling all of the Jest and TypeScript rules is good 😅
3. Continue to work (in separate PRs) to introduce Mocha/JSON/etc. configurations as appropriate

[rekmarks]

I love it.

To be clear, I have not reviewed the meaning of even 5% of the rules in this repo, but support this effort without reservation. I also agree with all of the points outline by @whymarrh where he tagged me.

[Gudahtt]

LGTM!