Request: Outline support

[clsheppard]

I concede there most dts nodes aren't deep, but some grow long. A list of nodes in the outline pane would help navigate long dts files and provide faster abstract understanding of the the dts file contents.
Also, Nice VS Code extension. Thanks.

[plorefice]

I've looked into what it would take to implement the outline pane support, and I'm afraid it's gonna be a lot of work, since it basically requires writing an AST parser.

I think it could also be done using plain regular expressions, but right now I don't really have much time to work on it. PRs are welcome though!

PS: thanks for the compliments!