Use handler to generate NationBuilder URLs

instead of config function

tailbone_nationbuilder/menus.py

@@ -24,10 +24,9 @@
 Common menus for NationBuilder
 """
 
-from rattail_nationbuilder.nationbuilder.util import get_nationbuilder_url
-
 
 def make_nationbuilder_menu(request):
+    app = request.rattail_config.get_app()
     url = request.route_url
 
     nationbuilder_menu = {
@@ -47,7 +46,7 @@ def make_nationbuilder_menu(request):
         ],
     }
 
-    url = get_nationbuilder_url(request.rattail_config)
+    url = app.get_nationbuilder_handler().get_url()
     if url:
         nationbuilder_menu['items'].insert(
             0, {

tailbone_nationbuilder/views/nationbuilder/donations.py

@@ -100,6 +100,18 @@ class NationBuilderCacheDonationView(NationBuilderMasterView):
 
         f.set_type('amount', 'currency')
 
+    def get_xref_buttons(self, donation):
+        buttons = super().get_xref_buttons(donation)
+
+        app = self.get_rattail_app()
+        nationbuilder = app.get_nationbuilder_handler()
+        url = nationbuilder.get_url()
+        if url:
+            url = f'{url}/admin/signups/{donation.donor_id}/donations/{donation.id}'
+            buttons.append(self.make_xref_button(url=url, text="View in NationBuilder"))
+
+        return buttons
+
 
 def defaults(config, **kwargs):
     base = globals()