Add expressway tagging to the transportation layer (#1313)

Fixes #1148 

This PR adds expressway tagging to the `transportation` layer, by setting `expressway=1` for non-motorway roads tagged `expressway=yes`, and omitting the tag otherwise.  Additionally, I've added a few unit tests to verify that the expressway tagging is being imported and updated into the intermediate tables.

Here is an example of expressway tagging on US-1 in Rhode Island, USA:

![image](https://user-images.githubusercontent.com/3254090/143501278-db3671b2-2efa-4998-bffd-9ddfec63579b.png)

tests/update/500_update-highway.osc

@@ -5,6 +5,13 @@
         Change tags
   -->
   <modify>
+    <way id="5002" version="1" timestamp="2019-01-01T00:00:00Z" visible="true">
+      <nd ref="500021" />
+      <nd ref="500022" />
+      <tag k="highway" v="primary"/>
+      <tag k="expressway" v="yes"/>
+      <tag k="name" v="OpenMapTiles Primary"/>
+    </way>
     <!-- Change tags -->
     <way id="5003" version="2" timestamp="2020-01-02T00:00:00Z" visible="true">
       <nd ref="500031" />