Add MaterialDesignToolBarToggleButton (name is just a suggestion) to make it look like MaterialDesignToolToggleListBox

[bebenins]

This idea came from this ticket, which turned out to be a new .NET behavior:
#3677

Basically would like to see a toggle/checkbox styled for ToolBar. Meaning, it looks just like a single-item MaterialDesignToolToggleListBox looks today. When unselected, just make it look flat as the rest of the ToolBar.

Not sure what's better for base, a ToggleButton or a CheckBox. I'm also not super proficient in styling on such low level so I would appreciate if someone could help. Thank you.

[corvinsz]

This comment is only somewhat related to this issue/enhancement, but I still decided to put this here:

I noticed this toggle behavior should already exist, but with a ListBox.
To show off this behavior I created a PR #3680 which actually makes the ListBoxItem toggleable in the demo app:

In the issue @bebenins linked above (#3677) I mentioned, that using a ListBox for this kind of behavior is in my opinion "the wrong tool for the job".
I'm open for more opinions on this.