Add VS Code multi-root workspace to DaisyExamples root

[stephenhensley]

It seems like we can potentially have the repo fully set up to work with VS Code.

Using a multi-root workspace we can have each example loaded, and select which to debug, or edit, etc.

You can still open projects individually from a single folder. So not a whole lot would change except that it would be possible to open a single workspace to work on many examples at once without having to open several instances of VS Code.

This also would have all of the library sources within the file hierarchy on the left side of the window, which would be a huge productivity booster on its own.