Add noUselessIndex to no-useless-path-segments

[rajsite]

Justification

Found code that was mixing usages of index imports and directory imports.

For example with the following npm package file structure:

- src
  - awesome
    - index.ts
  - other.ts

Some imports within the library would use import './awesome'; while others used import './awesome/index';.

In es6 modules world those resolve to two different absolute paths, ie C:/lib/src/awesome vs C:/lib/src/awesome/index so tooling that may not be aware of commonjs file resolution may treat them as different symbols. This is not a concern in modern versions of tooling that I have seen but enforcing the consistency seems useful anyway for readability.

This PR copies the exisiting airbnb rule for import/no-useless-path-segments and adds the noUselessIndex configuration.