Sync METADATA files (and/or all files) in the internal repo and this one

In https://github.com/google/fonts/pull/7930 I noticed that the designer key of `tajawal/METADATA.pb` was out of sync, and had the requested changes already (and were live already).

I can therefore see it would be good to have a python script that can check if the 2 int/ext repos are in sync - especially for METADATA stuff like designer, but also for all files.

Only Google FTEs can access the internal repo, so I guess @chrissimpkins is the best person to do this.

But I think maybe @m4rc1e has a script already to do something similar for gftools...?