Actions: Show/Hide Columns

[Borvik]

Provide UI in a dialog to show/hide columns

• [x] Provide selector to toggle visibility of columns
• [x] Provide custom function to call that receives columns and setColumnVisibility function.
  • Allows custom UI, custom UI developer would be responsible for managing their form state before passing it to setColumnVisibility.
• [x] Bonus: Show hierarchical drag-drop list to change visible order
  • Should have an option for each column to lock the order for that column
  • Grouped (nested) columns always move together and can't be separated
  • Add a setColumnOrder function to above override function

[Borvik]

Hierarchical drag-drop no more...

Grouped headers intelligently determined based on base column order.