Motivation for changes:

Reduce build time and distribution size for updates to docker image. #3748
Alternate implementation to #3749

Detailed changes:

• Optimize layers of docker images such that dep and webui layers don't need to be rebuilt/distributed when deps haven't changed
• Add a cache to github actions so that reused docker layers don't need to be rebuilt. More testing is needed how much this helps. Hopefully a lot, because with the cross-arch building that step takes a full hour to do without caching.
• Remove installation of cryptography library on builder image, which took a long time on multi-platform builds because it needed rust installed and to be compiled from scratch
• Split release requirements from dev requirements (turns out this was sort of unrelated to docker)

Addressed issues/feature requests:

• Fixes docker: reuse base docker image #3748

To Do:

• Figure out if this actually does what I think it does and makes things better