Update LocalStack images & runtime to python 3.10

This PR makes couple of significant changes to the build pipeline in order to fully support python3.10 features over the build pipeline:

• Usage of machine executors throughout the pipeline: In contrast to the current state, we now use machine executors for all steps of the pipeline, instead of just the steps needing docker. This is necessary due to the passing of the virtual environment from the install steps to later steps, and the difference in pathing between machine (using pyenv) and docker (installing in /usr/bin) images. Alternative would have been rebuilding the venv every time or trying to fix the venv paths for every job, which just begs for errors to occur.
• Update of machine images: In order to use python 3.10.3 throughout the pipeline (and 3.10.4 in the docker image), I updated the machine images to ubuntu-2004:2022.04.1, which is available for both arm64 and amd64 machine executors (https://discuss.circleci.com/t/ubuntu-linux-vm-machine-images-2022-april-q2-update/43749).
• In order to make future updating of machine images simpler, they are now defined as pipeline parameter on top of the config.yml file (split between amd64 and arm64, if different image versions should be necessary at some point, as was in the past), as well as the amd64 machine executor.
• Updating docker is not necessary anymore, due to the updated images.
• Adds python 3.10 as classifier in setup.cfg.

Other changes:

• Update dockerfile for python 3.10.4 (to include fixes also made by Update python to 3.8.13 #5856 )
• Update tests against pro for python 3.10