Consolidate eachdist logic between core and contrib

[pmcollins]

Can we consolidate this logic? I know that removing/replacing eachdist has been discussed, but while we still have it, would be nice to make it as easy to use and update as possible.

https://github.com/open-telemetry/opentelemetry-python/blob/main/scripts/eachdist.py

https://github.com/open-telemetry/opentelemetry-python-contrib/blob/main/scripts/eachdist.py

Originally posted by @pmcollins in #3947 (comment)