Run formatting scripts during PR builds

[dehoward]

Motivation and Context

brings in the renaming/consolidation changes from #60 and adds the format scripts to run as part of PR builds.
hopefully one day we will have automated fixing of the formatting errors, but for now they must be fixed by the developer manually.

Description

• fixes all formatting errors.
• updates READMEs to use relative links where possible since absolute links are not caught by markdown-link-check.
• github workflows:
  • adds copilot-format-frontend which runs yarn format to check if formatting is correct.
  • renames node-pr to copilot-build-frontend and removes the find-yarn-projects job from the workflow.
  • removes copilot-chat-package in favor of copilot-build-backend since the two workflows seem identical.
    also changes copilot-build-backend to run dotnet format, and also run when PRs are created.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[dehoward]

need to test dotnet format check