Summary of changes:
- Update the charmcraft.yaml file to use base and platforms, only
allowing noble support.
- Update config to default to caracal.
- Update osci.yaml to use the charmcraft 3.x/beta
- Drop non-noble tests
- Update constraints file from -2024.1.txt to -noble.txt
- Add charmbuild to .zuul.yaml
- Add TEST_JUJU3=1 to tox.ini to force Juju 3
Change-Id: I915bf4647e523a9c6f90c2549eab460c0c4cd23c
df934b2649