Add Dockerfile.sandbox for all projects with generator script

[marwan37]

This PR adds customized Dockerfile.sandbox files to all demo projects to support our upcoming VS Code sandbox containers.

1. Created Dockerfile.sandbox for all projects
2. Added generate_sandbox_dockerfile.py script that:
   • Automatically extracts project dependencies from requirements.txt
   • Detects API keys and environment variables by scanning project files
   • Generates properly formatted Dockerfile.sandbox files with project-specific configurations

Note: The workflow file for automatically building and pushing these Docker images will be submitted in a separate PR to avoid triggering simultaneous builds for all projects, which would overload the runner.

[strickvl]

@marwan37 for stuff like this, you might want to add someone to review these PRs, not only because it's good in general, but more so that people are aware of what functionality / code etc is in the code base. FYI for future PRs :)

[marwan37]

@strickvl You're absolutely right. I merged this one quickly to test the main functionality in the other open PR. I wanted to avoid pushing all project docker images to dockerhub at once... but then I found a safer approach 🙂. In any case, sorry about that, will definitely add reviewers to future PRs.