Add core24 to the workflow matrix

[Hook25]

This is the first update required to support core24:

• Adds the core24 image and test directory
• Updates the image/qemu vesion combination for jammy/core22 as there is a known bug, see: LP2096782
• Removes the squashfs workaround as the issue linked has been solved and the fix is released (also: it breaks core24 builds)
• Updates the maintainer in authors so that the old maintainer doesn't receive emails about this resurrected fork

This also removes the following:

• Removes podman support as it wont be supported for now
• Removes i386 as it wont be supported for now
• Removes amd64 as I currently see no point in cross building for amd64 Re added, makes sense for VM builds of core16

Passing tests: (tests are failing on the pr because I cancelled them to save some runner time and allow my other repo to get the runners)

• Build and test: https://github.com/Hook25/snapcraft-container/actions/runs/13262437308/job/37022637801
• Buld and push: https://github.com/Hook25/snapcraft-container/actions/runs/13263306462/job/37024600978

[p-gentili]

LGTM, just a double space to fix

[Hook25]

Cancelling the pipeline as the change is not really consequential