Add previous supported ServerAPI definitions

[Andy-Grigg]

Add previous versions of the Server API server definition to the project, and expose the bindings in separate namespaces, with names like v2024r2. This seems to work as expected, but there are a couple of points for discussion:

• I have removed the 'python package' information, because we now have more than one. We can continue to document this manually in the repo README, but I don't think there's much benefit in including this in the generated code. We include it for bomanalytics-openapi because you could conceivably end up on that package when you're looking for 'bomanalytics'. But you're unlikely to end up at https://pypi.org/project/grantami-serverapi-openapi/ because you were looking for RecordLists
• I have put the in-development 2025r2 bindings in v2025r2. This has the advantage of keeping things nice and easy as we transition from 25r2 development to hardening and release, but it maybe makes it look like v2025r2 is as stable as the other packages.
• There's no latest. Maybe this is ok? If we wanted to add it, we'd probably need to flag a certain definition as latest, and make a change to the template to include a special section in the top-level __init__,py for this package. It would need to go last in pom.xml though, to make sure it didn't get clobbered by subsequent builds which 'aren't' latest. Either that, or we'd need some clever runtime definitions to figure out which one is 'latest'.

[Andy-Grigg]

This PR is too big to reasonably review in GitHub, and the Files tab doesn't load properly because of the number of files. This should be the only time this happens though, since the files introduced in this PR won't be changed until they're deleted.