Update TDM README with Suggestions #2490

Overview

The TDM Calculator README should be updated with the suggested edits contained in this issue, so that the readme file's overall readability is improved, messaging is clarified, and content is updated.

Action Items

• Review suggested edits on this Google Doc
• If edits are acceptable, then follow one of two approaches:
  • Make each individual edit on the TDM README file OR
  • Approve all edits on the Google Doc and copy & paste the revised markdown text from the Google Doc into the TDM README file
• Submit PR with these edits

Resources/Instructions

• Google Doc with TDM README updates
• TDM README file
• Original PR that was submitted from a non HfLA github user with a portion of these suggested edits Updated Readme.md #1898
• Prior issue reviewing README suggestions: Review Readme suggestions #1918