Back button long-press navigation

[dcmartin]

From time-to-time there is a problem utilizing the "back button" provided for subviews, as well as other contexts.

To eliminate the various navigation issues associated with the concept of "previous" a new long press action would be added that would return the UI back to the top-level, i.e. Overview (aka "lovelace" file).

An extension of this behavior would provide options, e.g. dashboards available in addition to Overview, with icons and/or text distinctions.