Program Status Widget date issues

A PR to fix a few issues with the Program Status widget:

• You currently are able to edit the enrollment date a program to be after the start date of a state within the program
• When a program is closed, the most recent state in each workflow has it's end date set to the completion date, but this is not displayed to the user
• In the above use case, if the user attempts to transition to a new state that on a date that is before the completion date of the most recent state, it fails silently

This fix should:

• Not allow shifting enrollment date after the start date of any states in the workflow
• Display the end date of the most recent state if it has one
• Not allow a state transition date before the completion date of the most recent state (if the state has a completion date)

This should hopefully allow proper editing of states in all use cases, prevent bad data, but admittedly the editing UI may be less than ideal.  Generally, it becomes difficult to edit the state transitions of a closed program, or to edit the enrollment date of a program with states.  Generally, the best practice (currently) to edit these cases would be to "uncomplete" the program, remove the states, and then add them in the proper order with the proper states.