Updated table nodes to support soft deletes using the new field

'deleted_at' as Datetime and give us free metadata.
Updated Sqlite builder to test different scenarios for users and roles.
Updated NODE_FORM_RESPONSE.edit_form feature to add a delete operation iff
there is a node ie node id >0 and the current user has delete permission on it.
Updated NODE_HANDLER.do_post to handle the operation "DELETE".
Updated queries to retrieve nodes filter by no logical deleted rows (ie. deleted_at is NULL).
Updated CMS_USER_API.has_permissions. (authenticated_user_role seems to generic).

src/service/user/cms_user_api.e

@@ -49,7 +49,8 @@ feature -- Status report
 				if is_admin_user (a_user) then
 					Result := True
 				else
-					Result := user_role_has_permission (authenticated_user_role, a_permission)
+					fixme ("Check how to handle this predefined role")
+						-- Result := user_role_has_permission (authenticated_user_role, a_permission)
 					if not Result then
 						Result := across user_roles (a_user) as ic some user_role_has_permission (ic.item, a_permission) end
 					end