Make sidebar collapsible

[willgarrett64]

The sidebar will be collapsible, clicking on the left arrow to collapse it. In the top left of the page there will be a right arrow (or something similar) where the user clicks to open up the sidebar again.

For mobile, the sidebar will cover the whole screen.

It would be nice if there was an animation so that it actually slid open/closed.

These arrows should sit inside the main sidebar div so that we don't need to add these arrows to each individual sidebar. The individual sidebars content (sign in/countdown list/etc) will be a sibling of the arrows

I.e.

<div sidebar>
  <img src="arrows" />
  <div currentViewSidebar>
    sidebar content
  </div>
</div>