TableView, TreeTableView: Remove border around TableView, TreeTableView and related controls?

[dukke]

Check whether we should remove the border. This can especially be a problem when there is for instance a SplitPane separating the TableView from the other controls on the other side of the SplitPane. A double border will appear.
However it can also be true that without a border there is no "visual bounds" between the TableView and the rest of the UI.