Add "Path" field to the view-model viewer

[miyconst]

It would be very nice to have a [Path] field on top of the JSON view-model in the starcounter-debug-aid.

When debugging some issues it very often happens to check exactly the same value multiple times, and the view-models usually are very big, so it requires multiple clicks to get to the value.

The field should act same as Windows Explorer. When user navigates to somewhere, the value gets updated, when value is changed in the field, the tree view gets expanded and focused to the place pointed.

cc @warpech

[jwillmer]

Nice idea. I also like the search box on the right!

[alshakero]

Do you think this change is enough? The tree preserves expansion state across updates

[miyconst]

Yes, I think it's still a nice and required feature.