Description of the change

Moves source code options into a single command line codegen flag named source instead of having separate source and source-compression options.

Why am I making this change?

There's only three valid states for what to do with source code during code generation: omitted, compressed, and uncompressed. So let's replace two booleans with a single enum.

Checklist

• I've updated the relevant CHANGELOG files if necessary. Changes to javy-cli, javy-plugin, and javy-plugin-processing do not require updating CHANGELOG files.
• I've updated the relevant crate versions if necessary. Versioning policy for library crates
• I've updated documentation including crate documentation if necessary.