Introduce AddTeamToCodeowners Recipe

[sghill]

What's changed?

A new recipe has been introduced.

What's your motivation?

Closes #19.

Anything in particular you'd like reviewers to focus on?

The style-matching implementation is done in-recipe, there may be a better way to do this.

Anyone you would like to review specifically?

@timtebeek @basil

Any additional context

Checklist

• [x] I've added unit tests to cover both positive and negative cases
• [x] I've added the license header to any new files through ./gradlew licenseFormat
• [x] I've used the IntelliJ auto-formatter on affected files
• [x] I've updated the documentation (if applicable)