Support Activate and Retire actions on Process Definitions

The ODE console displays the status of process definition versions, which can include ACTIVE and RETIRED.

When in ACTIVE state, it should be possible for the console user to issue the 'Retire' action to change the process definition state to RETIRED.

When in the RETIRED state, it should be possible for the console user to issue the 'Activate' action to change the process definition state to ACTIVE.

It is assumed that if an existing version of a process definition is ACTIVE, and another version is 'activated', then ODE will automatically retire the current active version. This cannot be tested currently, as ODE 1.3.3 throws an exception in the ODE console when this is attempted.

If this mechanism is implemented, then it will provide a means for the current version of a process definition to be prevented from creating any new process instances. This is not currently possible in RiftSaw, as undeploying a process will terminate any existing process instances, and also has the effect of taking down the web service, and therefore making process instances associated with older versions of the process definition inaccessible (see RIFTSAW-137).