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 noble and oracular to charmhelpers
- Set env var in tox.ini TEST_JUJU3=1
- Add charmbuild to .zuul.yaml
Change-Id: If200e251b667c527a5c1aa9db293b6e0eda4a53d
cd5e40d495