Add support for materializecss in aspnet-codegenerator

Hi there,

It's a feature-request.

In general, the **aspnet-codegenerator --version 2.2.3** helps generating Views code using bootstrap. But I think, there are some other cool CSS frameworks which should be supported in this context.

At least, bring **materializecss** support for scaffolding and code-generation. By this time, modifying the bootstrapped html code to support materializecss seems much painful.

Thanks.