THRIFT-5000: Use per-version Docker build contexts

[kpumuk]

Fixing build error in the docker official images repo: https://github.com/docker-library/official-images/actions/runs/26417245079/job/79192738571?pr=21530

Copied the entrypoint script into each of the version directories, similarly to how Apache Storm is doing it.

• Did you create an Apache Jira ticket? THRIFT-5000
• If a ticket exists: Does your pull request title follow the pattern "THRIFT-NNNN: describe my issue"?
• Did you squash your changes to a single commit? (not required, but preferred)
• Did you do your best to avoid breaking changes? If one was needed, did you label the Jira ticket with "Breaking-Change"?
• If your change does not involve any code, include [skip ci] anywhere in the commit message to free up build resources.