wfs capability extension point

- Added an extension point for adding elements to wfs capability document as children of the ows:ExtendedCapabilities  element.
- Refactored WMS ExtendedCapabilitiesProvider to have a super class that is shared by the WFS ExtendedCapabilitiesProvider class.
- Updated wfs load the extensions when created capabilities document

Updated the community inspire module (at IGNs request) to add wfs ows:ExtendedCapabilities to make WFS inspire compliant.  WMS extended capabilities was slightly refactored to better share code with the wfs implementation.  Mostly package renaming of a few files.

This work was financed by IGN. (credit where credit is due)