Update MapLibre dependencies, add terrain editing (#859)

This PR aims at updating MapLibre dependencies.

The main goal of this update is to allow adding terrain specification to
the editor.
This requires version 4 of maplibre so currently it will use the
pre-release.

src/config/tokens.json

@@ -1,4 +1,4 @@
 {
-  "openmaptiles": "KDhMfHvorAFkFe64wlZb",
+  "openmaptiles": "get_your_own_OpIi9ZULNHzrESv6T2vL",
   "thunderforest": "b71f7f0ba4064f5eb9e903859a9cf5c6"
 }