Allow components/directives to use both element and attribute as selectors

[diagramatics]

Right now directive-selector and component-selector chooses between using attribute or element as the type, but you can't actually use both. I'd like to make a case for supporting having the two if it's not possible yet.

After listening to Angular Material team's talk in ng-conf about component API designs there is a case for using attribute selectors as components to allow components to be able to use the DOM API without needing to reflect 20+ bindings from the custom element style components to the inner DOM API it wraps. angular/material2 itself uses directives — which I'm not sure why directives instead of components — my case for using components would be for the scoped styling it provides compared to directives, which angular/material2 doesn't need to yet with their approach to having a global stylesheet with all the styles of the components.

I don't have a use case example for directives yet though, but considering the configuration of both rules are the same, maybe it's worth giving people the option to anyway.

[mgechev]

It's already possible to pass an array with elements ["element", "attribute"] for both. Another alternative is to disable the rules.

[diagramatics]

Ah my bad, thanks for the clarification.