dtext links: add basic index page.

app/models/dtext_link.rb

@@ -19,6 +19,18 @@ class DtextLink < ApplicationRecord
     links
   end
 
+  def self.model_matches(params)
+    return all if params.blank?
+    where(model_id: WikiPage.search(params).reorder(nil))
+  end
+
+  def self.search(params)
+    q = super
+    q = q.search_attributes(params, :model_type, :model_id, :link_type, :link_target)
+    q = q.model_matches(params[:model])
+    q.apply_default_order(params)
+  end
+
   def normalize_link_target
     if wiki_link?
       self.link_target = WikiPage.normalize_title(link_target)