Accessibility

[fhennig]

How good is it? What can we improve?

### Tasks
- [x] set html tag lang=en
- [x] footer logo needs alt text
- [x] for the footer FA icons, follow FA accessibility instructions: https://fontawesome.com/v5/docs/web/other-topics/accessibility#web-fonts-with-css-semantic-icons
- [ ] link color is low contrast, especially on grey rows in tables. how to fix?
- [x] browser zoom function apparently disabled by the `maximum-scale` attribute
- [ ] the version `select` element does not have a label
- [ ] the version `select` element uses JS jump navigation. It would be better to have a separate submit button. Or, maybe the whole select element can be replaced with a nav item? I.e: https://www.w3.org/WAI/tutorials/menus/flyout/