Set up RAT checks in CI

[andygrove]

Once the initial PR is merged, we should add RAT checks in CI before we start merging new PRs.

[andygrove]

@sunchao Can someone on your team take a look at this? Hopefully, you can copy the GitHub workflow from DataFusion for the Rust code, and reference Apache Spark for the maven part.

[sunchao]

Sure, will do. Yes I looked at the RAT tool in DF and we can pretty much reuse it I think

[sunchao]

I think we already have something in the CI to do the check. For instance here.

The check is done by the rat plugin and is applied to all files in the repo.

[andygrove]

Thanks @sunchao. I will close this issue.