Accessibility updates

[abbycabs]

Look into making the following updates on the website

### Tasks
- [ ] https://github.com/github/maintainermonth/issues/65
- [ ] text overlaps images
- [ ] fix tab order (current goes from menu on the side to the bottom of the site instead of main content)
- [x] animations during scrolling is an anti-pattern for accessibility

Huge thanks to @juliaferraioli for this list!

[david-mbugua]

Hello, in regards to the first task, which images exactly lack alt-text? I would like to contribute to that.
Thanks.

[abbycabs]

Thanks @david-mbugua! I don't see any alt text present, so as much as you can add would be great.

The graphics are by Ariel Davis, it would be nice to credit her in the alt text.
Thanks!

[david-mbugua]

Okay @abbycabs , I will credit her in the alt-text. Kindly assign me the issue. Thanks :)

[abbycabs]

@david-mbugua opened a separate issue for the alt-text, please comment there so I can assign you