Revise README.md for Consistency and Useability

[bboonstra]

Summary

This PR cleans up the README.md for accessibility, readability, and standardization.

• Corrects invalid html
• Removes dead links and adds new anchors
• Standardizes some markdown
• Aligns bullets, rows, columns, etc

Description

The current README gets the job done. However, it's quite messy when you try to edit it, it doesn't follow the markdown standards, has dead links/anchors, and there's an invalid paragraph closing tag (<p/>) at the top! I thought that, before I submitted a solution, it would be helpful to future contributors to have a cleaner README to edit.

How Has This Been Tested?

• The new README has been checked against the old one and is consistent when rendered.

Make sure all below guidelines are followed else PR will get rejected:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code so that it is easy to understand
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[welcome]

I can tell this is your first pull request! Thank you I'm so honored. 🎉🎉🎉 I'll take a look at it ASAP!