Document ows_service_onlineresource for WMS/WFS

[dmorissette]

In bug 375, a new ***_service_onlineresource metadata was added to specify
top-level WMS/WFS <Service>/<OnlineResource> value that can be distinct from the
GetMap/GetCapabilities onlineresources (wms_onlineresource).

Need to add this metadata to the WMS and WFS Server howtos. In both cases it is
web level metadata. In the WMS case we try to use values in the following order
(same for WFS):

1- wms_service_onlineresource
2- ows_service_onlineresource
3- wms_onlineresource (or automatically generated URL, see wms_onlineresource
rules in HOWTO)

[dmorissette]

Setting 4.4 release target.

[jmckenna@…]

added service_onlineresource notes to wfs_server and wms_server docs. committed
to cvs.