* GadgetTool_viewPrettyGadgetDialog is used to add a gadget in the current Knowledge Pad.
It previously used an sub EditorField to display the gadget image. Instead of this, replace it by a ImageField, which will be use to standardize the rendering and size of all screenshots.
* Add a new columns which shows the gadget description.
* Replace the custom listmethod GadgetTool_getGadgetList by the standard portal_catalog call.
* Use the portal type parameter to filter only Gadget.
* Use the default parameters's parameter to pass the value of gadget_type_uid.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@32218 20353a03-c40f-0410-a6d1-a30d3c3de9de