[IMPROV] Test data introspection extension for VSCode

[AlexVCaron]

Type of improvement

If submitting a new module or fixing a bug, please use the appropriate template.

• Documentation
• Development tools (e.g. linter, formatter, etc.)
• Development container
• Global update (please specify)
• Other (please specify)

Describe your improvement

Update the nf-scil-extension-package and create an extension to introspect test data easily from VSCode.

Describe how to test your improvement

1. Install Node.js 20 and npm on your system (check the devcontainer Dockerfile and onCreateCommand.sh files)
2. Open the repository in VSCode outside of the devcontainer
3. Change directory to nf-scil-extensions/test-data-treeview
4. Go to Run & Debug (Crtl+Shift+D)
5. Press play to launch the extension build
6. The new view is located in the Explorer pane, on the left. It should appread below all tabs (below Timeline on mine).

Checklist before requesting a review

• Ensure the syntax is correct (EditorConfig and Prettier must pass)
• Run the test suites if your changes affect any module
• Regenerate the Poetry lock file if you have updated the dependencies
• Ensure the documentation is up-to-date

[AlexVCaron]

@scilus/reviewers_nf-scil anyone wants to try to launch a VSCode and test the extension before publishing ?