upgrade old information values to subtypes of board/map

and add an "activity" field for maps and guideposts which indicates the mapped/signposted scope of activities: hiking, biking, etc.

closes #45

interim/source_strings.yaml

@@ -97,6 +97,16 @@ en:
           'yes': Public
         # 'terms: permitted,private,public'
         terms: '[translate with synonyms or related terms for ''Allowed Access'', separated by commas]'
+      activity:
+        # 'hiking=*, bicycle=*, mtb=*, horse=*, ski=*'
+        label: Activity
+        options:
+          Ski: Skiing
+          bicycle: Cycling
+          hiking: Hiking
+          horse: Horseriding
+          mtb: Mountainbiking
+        terms: '[translate with synonyms or related terms for ''Activity'', separated by commas]'
       addr/interpolation:
         # 'addr:interpolation=*'
         label: Type