Search inside resources / hierarchies using `parent`

[joepio]

@Polleps is currently exploring resource scoped full text search.

We want to use this in (at least) these ways:

• by default search only inside the currently selected Drive.
• Users should be able to search inside any resouce.

Searching inside resources

Some usecases:

• Search inside a chatroom for some message
• Find a file in a deelply nested folder

UI options:

• Add a search inside button to the navbar (or maybe only in the menu). When this is selected, add a pill that can be closed to the search bar.
• Show a search inside option in the search bar itself, available after typing. This requires that we don't navigate away when typing, so the dialog search implementation seems a good idea here. (see #171).

Implementation thoughts:

• The useServerSearch hook should probably get a new option for parent