Support adding and removing table columns

This adds support for adding and removing columns in the
data table view. Now, the user can right-click on the header
and add new columns and remove existing columns in the table.

Change-Id: I1f69d80446a7f968024280c8ff222fb1fc26c5c6
Add support for moving table columns

This adds support for reordering the columns in the table
view. Now, the user can drag-and-drop columns in the table
view.

Change-Id: I9dca5650feef8b88d6d185d8dfce16b74d5f0cd6