Add component title to left nav

[eric-schneider]

We don't provide users with an easy way to identify which component they're currently viewing. This is a big problem for wayfinding (especially for users arriving from Google search), and will continue to be a problem even after we introduce the global nav.

A good first step would be to add the component title to the top of the left nav. It should probably also be a link to the component start page (same as the breadcrumb). If the component has a version switcher, the title should sit adjacent to the version dropdown toggle.

NOTE: we should make sure to test long component titles to ensure that long titles wrap appropriately.

[eric-schneider]

@colegoldsmith I noticed that the version switcher got moved above the component title in the left nav. I thought it was supposed to be next to the component title (like in the screenshot above), but maybe there was a decision to reverse course that I wasn’t aware of?

[colegoldsmith]

Resolved with #159