Use jammy's python3.10-dev once we migrate from ubuntu focal to jammy

[kaoudis]

Joe and I broke down updating things (while the move away from polytracker-llvm is in progress) to dependencies that are compatible with Apple silicon as well as amd64 (Linux, Intel Mac) environments into a couple discrete changes. Prerequisites:

• remove Python version changes from examples: DaeDaLus nitf parser demo #6508 so it can be merged
• ensure polytracker works with python 3.10, which is required for Apple silicon and is only available from deadsnakes PPA on ubuntu focal, but can be found in the default jammy repos Update Python version to support new version of Ubuntu in polytracker-llvm #6495
• migrate all polytracker images from focal to jammy so that we can have more modern dependency versions, including clang, go, python, etc Update Dockerfile to build with latest gllvm polytracker-llvm#13

This issue is a reminder to (once we are on jammy):

• remove deadsnakes PPA and related dependencies from base Dockerfile in this repo (used as an intermediary step so that we could split out python versioning issues from all other possible issues we shall encounter as we migrate) and replace with jammy default python3.10-dev package

[kaoudis]

bumping the base Dockerfile(s) to jammy probably means bumping all the demo Dockerfiles in examples/ as well for consistency