Add tag to hide editor entirely (for plugins)

[dreamflasher]

Plugins such as Kanban and JSheets don't need the editor view, in fact it's stealing valuable screen space.
It would be great if the presistant layout plugin would have an additional tag layout:hide, which hides the editor/richtext view.

[MattDemers]

Agreed; I found this plugin mostly to have a "clips" notebook that didn't need to be edited at all, and to default to the "viewer" layout.