Stubbing out page layout with material UI

[Martskin]

In this PR:

• Stubs out page layout using material UI.
• Adds material ui to storybook for comparison with Bootstrap.

[Martskin]

We should probably pick Bootstrap or Material. They can live together but probably shouldn't.

• The front page design concept by @abell95 uses Bootstrap

• Material was added in this PR. https://github.com/BendJS/bend-community-site/pull/14

[russtaylor]

Agreed, that we should definitely go with either Bootstrap or Material. I personally am partial to Material.

This looks good to me!