Investigate feasability multiple Python-from-Rust packages

[felixhekhorn]

after #384 has been solved, we could investigate the possibility to ship multiple Python packages corresponding to the different Rust crates (e.g. ekore, dekoder). This feature may become complicated in the deployment - @alecandido tried in the past and didn't find an easy solution. For example consistent versioning might be a problem (but it is non-trivial already https://github.com/NNPDF/eko/blob/77d99363df23382bd3b7a3fa513bba213767d77c/crates/bump-versions.py ).

The current version of having a single Python packages (eko-rs) is not too bad - it is just potentially too big

[alecandido]

Consider that even NumPy and SciPy are shipping a single package containing different sub-packages, possibly covering different scopes.

My opinion is that, unless that's a proven bottleneck, you may ignore the issue. Though, you may want to monitor whether there are easy solutions available, just to keep it as an alternative.