Clarify and make optional the role of VS Code, also support rendering in browser or diagrams.net desktop app

[timblaktu]

Same issue as here, but instead of "just install VS Code", I would suggest that this (excellent!) tool:

1. Explain in the documentation, and in the tool output that it assumes you have vs code installed and will automatically try to open the generated diagram in it. This was confusing for me first time using the tool, I selected the options and then Quit in the terminal, then it asked me if I want to save the diagram. (Um, of course I do, isn't that the primary purpose of this tool?)
2. Make the vscode rendering step optional, and/or even better,
3. Support loading the diagram in a browser window at diagrams.net (or the desktop app, if installed)