The other GWC integration tasks in this group need to at least be configurable as they need to be enabled/disabled.
Since right now the only mention to GWC in the configuration UI is a link to the raw GWC form, we'll need to keep a link to that form while at the same time being able to:
- enable/disable WMS integration
- enable/disable disk quota limits
- set a global disk quota limit
(there's a lot more that can be done, but this is just a short term start)