Entry in context menu for split person

Currently split person is only applicable via a shortcut. We should add an option to the context menu.

added GUI usability labels

created branch 462-entry-in-context-menu-for-split-person to address this issue

assigned to @d.kilic

mentioned in merge request !330 (merged)

closed with merge request !330 (merged)

mentioned in commit 1e02eda7