Cleanup of svg files, move matchpoint to explicit layer

assets/layers/matchpoint/matchpoint.json

@@ -0,0 +1,13 @@
+{
+  "id": "matchpoint",
+  "description": "The default rendering for a locationInput which snaps onto another object",
+  "source": {
+    "osmTags": {
+      "and": []}
+  },
+  "mapRendering": [{
+    "location": ["point","centroid"],
+    "icon": "./assets/svg/crosshair-empty.svg"
+  }]
+
+}