Flesh out the acknowledgements & align with rest of project

The Acknowledgements page was just added to the editor https://gsa.github.io/openacr-editor/acknowledgements

We can either delete the **Major Contributors** or add Daniel, me (Mike), Owen & Danita. I'm fine with deleting it or populating it.

Both **Major Contributors** & **Project Team** should be in Sentence case. Just noticed that.

Ultimately it should align with what we have in our CONTRIBUTIONS.txt & AUTHORS.txt. I don't much care how we do this. Certainly it would be easiest if they were ordered in the same way so that there was less to maintain.

How do we want to reference organizations like NASA & the W3C who we have referenced broader ideas from?

Occurred to me that we might also want to add a section around the acknowledgements to do a small colophon around the editor where we can highlight the software used to create this site. This would include references to the W3C of course.

Some of this would be different for the editor & the website, but don't think it is worth adding this to the website at this point...

Original PR & comments - https://github.com/GSA/openacr-editor/pull/42#pullrequestreview-870738042