Adding a (untyped) dependency relationship between Node Templates

It should be possible to add a dependency between Node Templates without having to change their respective type definitions. This enables service templates to be easily "tweaked" to address ordering issues and is often useful in support, testing and debugging scenarios.

Note that we should not advocate this practice to avoid defining explicit relationships in Node Type designs. If a node truly has a dependency on another it should be part of the Node Type design, i.e. handled by the designer of the Node Type. It should be considered bad practice for users to have to know to add additional or special dependencies in order to use Node Templates in their topologies.