message: add best practices link and review information
diff: -[Things to note: Pull Requests **must** fix an issue. Discussion about the feature / bug takes place in the issue, discussion of the implementation takes place in the PR. Please also see the [Contributing Guide](https://github.com/smartdevicelink/sdl_core/blob/master/.github/CONTRIBUTING.md) for information on branch naming and the CLA.
  +[Things to note: Pull Requests **must** fix an issue. Discussion about the feature / bug takes place in the issue, discussion of the implementation takes place in the PR. Please also see the [Contributing Guide](https://github.com/smartdevicelink/sdl_core/blob/master/.github/CONTRIBUTING.md) for information on branch naming and the CLA, and the [SmartDeviceLink GitHub Best Practices](https://d83tozu1c8tt6.cloudfront.net/media/resources/SDL_GitHub_BestPractices.pdf) document for more information on how to enter a pull request. Once this PR is ready for review, please request one from @jordynmackool.
  Delete the above section when you've read it.]
  