[WIP] Expanded road route attributes (#1620)

This PR replaces the `route_N` attribute scheme with individual attributes for name and colour on routes.  Thus you will have:
* `route_N_network` to hold the route `network` value
* `route_N_ref` to hold the route `ref` value
* `route_N_name` to hold the route `name` value
* `route_N_colour` to hold the route `colour` or `ref:colour` value

layers/transportation/mapping.yaml

@@ -102,10 +102,6 @@ name_de_field: &name_de
   name: name_de
   key: name:de
   type: string
-short_name_field: &short_name
-  key: short_name
-  name: short_name
-  type: string
 tunnel_field: &tunnel
   key: tunnel
   name: is_tunnel
@@ -236,7 +232,6 @@ tables:
     - *name_de
     - name: tags
       type: hstore_tags
-    - *short_name
     - *tunnel
     - *bridge
     - *ramp
@@ -316,7 +311,6 @@ tables:
     - *name_de
     - name: tags
       type: hstore_tags
-    - *short_name
     - *tunnel
     - *bridge
     - *ramp
@@ -354,7 +348,6 @@ tables:
     - *name_de
     - name: tags
       type: hstore_tags
-    - *short_name
     - *tunnel
     - *bridge
     - *ramp
@@ -393,7 +386,6 @@ tables:
     - *name_de
     - name: tags
       type: hstore_tags
-    - *short_name
     - *tunnel
     - *bridge
     - *ramp
@@ -491,6 +483,9 @@ tables:
     - name: colour
       key: colour
       type: string
+    - name: ref_colour
+      key: ref:colour
+      type: string
     mapping:
       route:
       - road