[Improvement] find a better way to check for license in .md files

### What would you like to be improved?

Currently, we have added .md files in the doc directory to the Rat exclude list.

### How should we improve?

Find a better way of doing this.

Start by locating the RAT configuration and the exclusion of .md files under the doc directory. Determine how license checking currently handles those files; done means the documentation no longer needs the broad exclusion and the repository's RAT check still passes.

Written by the indexing model from the issue text.