Move unknown organisation logic into Jinja

Human readable content like this doesn’t really belong in the model
layer, it’s more natural to have it in the presentation layer.

app/formatters.py

@@ -520,5 +520,7 @@ def format_billions(count):
     return humanize.intword(count)
 
 
-def format_yes_no(value):
-    return 'Yes' if value else 'No'
+def format_yes_no(value, yes='Yes', no='No', none='No'):
+    if value is None:
+        return none
+    return yes if value else no