Added dprint config and commit-on-master task

[JoshuaKGoldberg]

👉 See #65993 Using a formatter for formatting (instead of lint rules) for context.

Corresponds to the changes described in #65993. This initial PR adds:

• .github/workflows/format-and-commit.yml: adds a workflow to run dprint and commit changes
  • Note that the trigger to run on master is commented out
• .vscode/extensions.json: recommends the dprint extension
• .vscode/settings.template.json: sets VS Code to format with the dprint extension by default
• dprint.json: configuration file for dprint, including "excludes" for (known or seemingly) auto-generated packages
• README.md docs around formatting
• package.json: a new dev dependency on dprint

Because format-and-commit.yml's commit trigger is commented out, merging this PR won't cause dprint to be applied to all files.

Co-authored-by: @jakebailey

[jakebailey]

Just as a meta-note about the workflows, I'd prefer if job configs were to come last; they get long and having them at the top will push info like the name/triggers/etc down to the bottom when it's usually important info. I don't think I've seen jobs stuck at the top before.

[typescript-bot]

@sandersn, @jakebailey, @andrewbranch, @peterblazejewicz Thank you for reviewing this PR! The author has pushed new commits since your last review. Could you take another look and submit a fresh review?

[jakebailey]

#66235 (comment) shows the new dangerbot output.

[jakebailey]

Okay, this PR should be ready to go, whenever we're ready to flip the switch! It'll immediately format about 141 files.

[andrewbranch]

👏

[typescript-bot]

@jakebailey, @sandersn, @peterblazejewicz Thank you for reviewing this PR! The author has pushed new commits since your last review. Could you take another look and submit a fresh review?

[jakebailey]

Ready to merge

[jakebailey]