CI: rework caching and build/test environment

[Harvester57]

Hi !

This PR is providing the following changes:

• A rework of the caching mechanism to make it work also on Windows build and use the native setup-python action cache mechanism
• Enhance the test and build steps to support all stable versions of Python currently supported by the app

Here is the Gemini-generated highlights:

• CI Environment Setup: The CI setup action (common-setup) has been updated to use pipx for Poetry installation, replacing the previously used abatilo/actions-poetry action. This change streamlines the Poetry setup process.
• Dependency Caching Optimization: Dependency caching for Poetry projects now leverages the built-in cache: poetry feature of actions/setup-python. This eliminates the need for a separate actions/cache step dedicated to Poetry dependencies, simplifying the workflow and potentially improving cache hit rates.
• Explicit Poetry Environment Management: An explicit step poetry env use ${{ inputs.python_version }} has been added. This ensures that Poetry correctly identifies and utilizes the specified Python version for the project's virtual environment, enhancing consistency across CI runs.
• Configurable Poetry Version: A new input poetry_version has been introduced to the common-setup action, allowing the specific version of Poetry to be installed to be configured externally. The default version is set to 2.1.3.