feat: @amplitude/eslint-config-typescript

[jooohhn]

Summary

Solves linting

• Create new @amplitude/eslint-config-typescript package
• Fixes yarn lint
  • Current project structure didn't work because eslint has a special way of managing shareable configs that requires prefixing configs with eslint-config
• Caveat: Currently unable to test locally with lerna. There seems to be a problem with linking unpublished local lerna packages with the other packages.
  • However, we can test manually by running yarn link in packages/eslint-config-typescript, then yarn link "@amplitude/eslint-config-typescript && yarn link" in each package
• TODO in another PR(s)
  • Will need to create another PR once we publish @amplitude/eslint-config-typescript to add it to each package
  • Will need to fix linting problems. Probably best to do after current open PRs are merged to avoid merge conflicts

Checklist

• [x] Does your PR title have the correct title format?
• Does your PR have a breaking change?: NO

[kelvin-lu]

@jooohhn the local linking with lerna might be because you're not declaring it as one of the workspaces in the top level package.json. But, I think it might make sense that this isn't treated as a workspace dir since you can't do other things that we need for validation (testing, building, etc.)