refactor(lib): go back to monorepo with 2 packages

[jeertmans]

With Rye, it seems to be finally possible to have Python monorepos.

Currently, the layout would be

differt
-> differt-core

and publishing both packages, but I also consider doing

differt-dev
-> differt (depends on differt-core)
-> differt-core

A few TODOs:

• Fix failing test for some plotting backend (missing modules seems to fail)
• Update CI to use Rye
• Update .readthedocs.yaml to use Rye (or install the package correctly)
• Split the API document in two: differt and differt-core`
• Test if we can publish the two packages separately (differt-core via pre-built wheels for each platform and differt one using any-* wheels)
• Avoid duplicate definition from both differt and differt-core (e.g., graph modules)
• Update the .gitignore file
• Setup correct Cargo.toml for workspace (currently we have a warning)
• Create a separate tests folder for differt-core?
• Fix type hint issues
• Add missing module documentation for differt-core
• Update differt-core's README and pyproject.toml file
• Dynamically resolve the version of all packages

[github-actions]

[LanguageTool] _{reported by reviewdog 🐶}
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[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 88.81%. Comparing base (d37d91d) to head (48f2001).
Report is 1 commits behind head on main.

❗ Current head 48f2001 differs from pull request most recent head e2a3e05. Consider uploading reports for the commit e2a3e05 to get more accurate results

Files	Patch %	Lines
differt/src/differt/rt/utils.py	60.00%	2 Missing ⚠️
differt/src/differt/scene/sionna.py	92.30%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #81      +/-   ##
==========================================
+ Coverage   86.71%   88.81%   +2.10%     
==========================================
  Files          18       35      +17     
  Lines         572     1252     +680     
==========================================
+ Hits          496     1112     +616     
- Misses         76      140      +64     

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[github-actions]

Rust benchmark results:

group                                                       before                                 changes
-----                                                       ------                                 -------
complete_graph_all_paths/iter                               1.02     23.6±0.16ns 40.5 MElem/sec    1.00     23.1±0.55ns 41.3 MElem/sec
complete_graph_all_paths_array_chunks/1                     1.14     38.1±0.18ns 25.0 MElem/sec    1.00     33.3±0.53ns 28.6 MElem/sec
complete_graph_all_paths_array_chunks/10                    1.06    352.6±2.23ns 27.1 MElem/sec    1.00    331.1±2.82ns 28.8 MElem/sec
complete_graph_all_paths_array_chunks/100                   1.00      2.5±0.02µs 38.5 MElem/sec    1.01      2.5±0.02µs 38.1 MElem/sec
complete_graph_all_paths_array_chunks/1000                  1.00     22.4±0.14µs 42.6 MElem/sec    1.00     22.3±0.26µs 42.8 MElem/sec
di_graph_from_complete_graph_all_paths/iter                 1.00    231.8±2.51ns  4.1 MElem/sec    1.03    237.6±4.14ns  4.0 MElem/sec
di_graph_from_complete_graph_all_paths_array_chunks/1       1.09    267.0±6.07ns  3.6 MElem/sec    1.00    244.4±3.07ns  3.9 MElem/sec
di_graph_from_complete_graph_all_paths_array_chunks/10      1.08      2.9±0.02µs  3.3 MElem/sec    1.00      2.7±0.03µs  3.6 MElem/sec
di_graph_from_complete_graph_all_paths_array_chunks/100     1.08     26.2±0.35µs  3.6 MElem/sec    1.00     24.1±0.49µs  3.9 MElem/sec
di_graph_from_complete_graph_all_paths_array_chunks/1000    1.13    261.2±2.27µs  3.7 MElem/sec    1.00    231.6±2.05µs  4.1 MElem/sec

[github-actions]

[LanguageTool] _{reported by reviewdog 🐶}
File types are normally capitalized. (FILE_EXTENSIONS_CASE[1])
Suggestions: HTML
URL: https://languagetool.org/insights/post/spelling-capital-letters/
Rule: https://community.languagetool.org/rule/show/FILE_EXTENSIONS_CASE?lang=en-US&subId=1
Category: CASING