Remove old position-on-read board column code
Summary: Ref T10010. This retires the old way of doing things inside ColumnPositionQuery. It is now obsolete and lives in BoardLayoutEngine instead.
- Moved cards, created cards, swapped filters, orders, etc.
- Some degree of unit testing coming in the next diff.
Reviewed By: chad
Maniphest Tasks: T10010
Differential Revision: https://secure.phabricator.com/D15177