Move to typescript-eslint

TSLint is going to be deprecated in 2019. Read here 👉 https://github.com/palantir/tslint/issues/4534

We need to migrate to [typescript-eslint](https://github.com/typescript-eslint/typescript-eslint) soon.

- Can start by converting [tslint-to-eslint-config](https://github.com/typescript-eslint/tslint-to-eslint-config).