Add component.json

Since 5.0 introduces better support for using inuit.css as a submodule/package I think we should include a component.json which is used by Bower.

We've touched on this issue before in #28 but support for using inuit.css as a package is better now like I said.

I've also [created](https://github.com/kevva/generator-inuit) a yeoman generator for inuit.css, as an alternative for your web template, which sets up a project with inuit.css installed as a Bower component.