Refactor Docker setup, follow best-practices in containerization and make caldera easier to deploy

[daw1012345]

Description

This project is currently quite difficult to get working. This is one of (at least) three pull requests intended to make caldera simpler to deploy or get running locally. Docker is a great tool for this, and should be the easiest and quickest deployment option.

Unfortunately, the current Dockerfile doesn't even build (due to an outdated version of Ubuntu).
This PR:

• Updates the Dockerfile to use a staged build to compile the UI and copies it over to the final container. This avoids the dance of installing node and npm, building the UI, then removing node and npm.
• Ensures that previous builds of caldera do not pollute the build within the container. For example, if caldera was ever compiled outside of Docker (especially the UI), it will not be recompiled in the container. This can cause a large headache, for example when the Docker build does not re-build the UI when the VITE_BASE_URL was changed.
• Containers should contain all basic requirements for all of the functionality to work. For example - if a container is compiled without emu support and then published to DockerHub, a user will not be able to easily get all the dependencies into the container (without modifying the Dockerfile and building it themselves). This PR ensures this is the case.
• The emu and atomic plugins depend on large submodules to work, but are capable of fetching them when they are enabled. This PR introduces two flavours of images - slim and full. The full (default) flavor contains said submodules to allow the container to work in environments without an internet connection, while the slim flavour disables the plugins and only fetches the submodules when they are enabled.
• Modify the workflow to build and push both slim and full images to GHCR (tagged appropriately).
• Adds a dependency on setuptools to work with recent versions of Python3
• Makes Docker the recommended deployment option in the README

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

Repeated build tests of both flavors of caldera (full + slim). The resulting containers appear to work when interacted with.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• [NOT RELEVANT] I have added tests that prove my fix is effective or that my feature works