Add dart_skills_lint to devtools and configure it to run in the cli and in tests

[reidbaker]

• add dart skills lint test and yaml config with instructions for how to use
• Add ignore file for valid links that are triggering false positives
• resolve readme to correct location

Pre-launch Checklist

General checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read the Flutter Style Guide recently, and have followed its advice.
• I signed the CLA.
• I updated/added relevant documentation (doc comments with ///).

Issues checklist

• I listed at least one issue that this PR fixes in the description above.
• I listed at least one issue which has the contributions-welcome or good-first-issue label.
• I did not list at least one issue with the contributions-welcome or good-first-issue label. I understand this means my PR might take longer to be reviewed. But I asked kenzie first.

Tests checklist

• I added new tests to check the change I am making...
• OR there is a reason for not adding tests, which I explained in the PR description.

AI-tooling checklist

• I did not use any AI tooling in creating this PR.
• OR I did use AI tooling, and...
  • I read the AI contributions guidelines and agree to follow them.
  • I reviewed all AI-generated code before opening this PR.
  • I understand and am able to discuss the code in this PR.
  • I have verifed the accuracy of any AI-generated text included in the PR description.
  • I commit to verifying the accuracy of any AI-generated code or text that I upload in response to review comments.

Feature-change checklist

• This PR does not change the DevTools UI or behavior and...
  • I added the release-notes-not-required label or left a comment requesting the label be added.
• OR this PR does change the DevTools UI or behavior and...
  • I added an entry to packages/devtools_app/release_notes/NEXT_RELEASE_NOTES.md.
  • I included before/after screenshots and/or a GIF demo of the new UI to my PR description.
  • I ran the DevTools app locally to manually verify my changes.

This does not need release notes because it adds tests and instructions for contributors only.

[reidbaker]

These are required because of flutter/skills#83 which will be addressed by flutter/skills#84