Provide a devcontainer to be used in Codespace

[turnmanh]

Is your feature request related to a problem? Please describe.

Currently, people have to install the toolbox to run the tutorials and start using it. With a devcontainer, they could start exploring and using the toolkit right away.

Describe the solution you'd like

Provide a devcontainer and a toolkit-specific Docker image. The devcontainer should have the req. VS Code extensions installed right away. This would fix #554 as well.

• [ ] ./devontainer incl. VS Code config.
• [ ] Dockerfile setup to run the toolkit

Describe alternatives you've considered

Include launch binder but that would limit the usability. (#554)

[turnmanh]

@Ziaeemehr, your intention to provide a Docker image would also support this proposal.

[janfb]

related to #1056