Explore detecting workspace roots automatically

[vinistock]

I think we may be able to auto-detect workspaces, in addition to letting users configure multi-root workspaces.

Instead of looking for the lockfile in the directory the user opened the editor, we can follow the same approach Bundler uses to locate the bundle, which is by searching up parent directories.

That would allow people to open VS Code in a directory inside the application's top level, but the LSP would still be operating from that top level project root, giving access to everything the project declares.

Not sure how easy it is, so this issue is for prototyping.

[gill876]

Yes please!

I think it used to work before, but ever since version 0.9.7 I have to open the project directory instead of the parent directory.