feat: add surface tag values "chipseal", "bitmac" and "tarmac"

Ways labelled with OSM tag `surface` set to "chipseal", "bitmac" or "tarmac" are classified as surface type "Asphalt" rather than "Unknown". According to OSM wiki most of chipseal and bitmac surfaces are likely tagged as `surface=asphalt`, whereas `surface=tarmac` is often incorrectly used for asphalt/concrete surfaces as actual tarmacadam is very unusual.

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

@@ -60,7 +60,7 @@ public static SurfaceType getFromString(String surface) {
  return switch (surface.toLowerCase()) {
  case "paved" -> SurfaceType.PAVED;
  case "unpaved", "woodchips", "rock", "rocks", "stone", "shells", "salt" -> SurfaceType.UNPAVED;
- case "asphalt" -> SurfaceType.ASPHALT;
+ case "asphalt", "chipseal", "bitmac", "tarmac" -> SurfaceType.ASPHALT;
  case "concrete" -> SurfaceType.CONCRETE;
  case "paving_stones", "paved_stones", "sett", "cobblestone", "unhewn_cobblestone", "bricks", "brick" -> SurfaceType.PAVING_STONE;
  case "metal" -> SurfaceType.METAL;