Rule proposal: no-rename-default

Consider the following:

components/foo.js:

```jsx
export default class Foo extends React.Component {
render() {
// ...
}
}
```

widgets/foo.js:

```jsx
import FooComponent from '../components/foo';

export default class Foo extends BaseWidget {
constructor() {
super(FooComponent);
}

// ...
}
```

`Foo` (in components/foo.js) and `FooComponent` are exactly the same thing, but have been renamed via default import/export. When one thing has two or more names, it increases the difficulty of comprehending code, especially when there are many functions, classes, etc. that are renamed on import.

The proposal is to have a rule that generates a warning or error when a default `import` is given a different name than a default `export`.

Use the components/foo.js and widgets/foo.js examples as the behavioral starting point, then locate the plugin's rule entry points and test conventions. Define the cases covered by the proposed warning or error, including when a default import name differs from its default export name, and add tests showing the completed behavior.

Written by the indexing model from the issue text.