Update status of Concept Exercises

[ErikSchierboom]

Concept Exercises can have a status specified in their "status" field in their config.json entry, as specified in the spec. This status can be one of four values:

• "active": The normal state of active exercises.
• "wip": A new, work-in-progress exercise not ready for public consumption.
• "beta": A new, active exercise that you want feedback on.
• "deprecated": An old exercise that is no longer active.

The "status" key can also be omitted, which is the equivalent of setting it to "active".