Add a banRepositories rule

This rule is needed so that we can enforce the "no repositories" requirement of Maven Central Repository.

I would see something like (these would be defaults>

<banRepositories>
<allowSnapshots>true</allowSnapshots> <!-- if a repo can resolve -SNAPSHOTs, I'm ok with it being in the pom -->
<allowReleases>false</allowReleases> <!-- if a repo can resolve releases, these two defaults would result in -SNAPSHOT only repositories being allowed by default -->
<ignoreRepositories>
<!-ignoreRepository>id of repository</ignoreRepository->
</ignoreRepositories>
</banRepositories>