ComponentDefinition type

Currently, there is no clean way to type check for a `ComponentDefinition`, e.g.:

```hbs
{{validated-component someComponent=(component "some-component')}}
```

The `(component)` helper returns a [`CurlyComponentDefintion`](https://github.com/emberjs/ember.js/blob/2f32bf3fd7981d05dda4bac5c2a7c680c676d265/packages/ember-glimmer/lib/component-managers/curly.ts#L447), which is a subclass of [`ComponentDefintion`](https://github.com/glimmerjs/glimmer-vm/blob/87da370aa5a73355b67643a58c2a6f43a3ba8924/packages/%40glimmer/runtime/index.ts#L59) of the [`@glimmer/rutime` package](https://github.com/glimmerjs/glimmer-vm/tree/87da370aa5a73355b67643a58c2a6f43a3ba8924/packages/%40glimmer/runtime).

Ideally, I would like this API:

```js
import Component from '@ember/component';
import { argument } from '@ember-decorators/argument';
import { type } from '@ember-decorators/argument/type';
import { ComponentDefinition } from '@ember-decorators/argument/types';

export default class ValidatedComponent extends Component {
@argument
@type(ComponentDefinition)
someComponent;
}
```

However, I don't see an easy way to access the `ComponentDefinition` interface / class from the Ember world.