SEO/Accessibility Improvements

[tbenbow]

Currently the top section of a page will get an h1 and all other headlines will be h2. We should take this further by...

1. Making sure all headlines use appropriate heading tags.
2. Add Footer, Header and Main tags to pages
3. Confirm alt tags are correct (sometimes they should be blank)

In general the goal is for Microgen sites to pass accessibility and SEO scans with minimal effort on the end users part.