feat: make highway:corridor foot-routable

Newer presets for mapping editors tend to start including more and more
corridors.
We should at least allow foot routing on them.

Author: koebi

ors-engine/src/main/java/org/heigit/ors/routing/graphhopper/extensions/flagencoders/FootFlagEncoder.java

@@ -116,7 +116,8 @@ protected void setProperties(PMap properties, boolean blockFords) {
                 "living_street",
                 "track",
                 "residential",
-                "service"
+                "service",
+		"corridor"
         ));
 
         avoidHighwayTags.addAll(Arrays.asList(