[Feature Request] Allow parent selection in Treeview filter out childrens from output

[stockmind]

Problem to solve

Currently isn't possible to get only the key or objects of most inclusive parents selected (and single nodes), this is handy to keep in a DB only the references to the most inclusive nodes.

Proposed solution

Add an option to the treeview component to let return only the upper parents and single nodes selected in the v-model. Graphically it should work as it does now, but the data returned back should exclude children if a parent is selected as in the Fiddle proposed: https://jsfiddle.net/g50odsmy/

In this fiddle i remove all the childrens before output.
In the V-TreeView code it should be possible to let the system flag children of parents selected but return only parents and single nodes selected if a flag is specified.