Consider dropping 3.0, 3.1, 3.2, 3.3 and 3.4 schemata

[dimaqq]

According to the Juju Roadmap, following Juju series have reached end of life last year:

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4

Meanwhile, the schemata are still included and used in https://github.com/juju/python-libjuju/tree/main/juju/client

The proposal is to remove the old schemata and regenerate the client code.

[dimaqq]

To do that, we'd have to update client code for one of the facades that's going away.
See https://github.com/juju/python-libjuju/blob/main/juju/client/facade_versions.py#L48