Feature request: add an option to show amenity=parking

[alexander-ii]

That will turn the service into a map of all kind of parking: areas and lanes.

[tordans]

This feature was added in https://github.com/zlant/parking-lanes/commit/59e2ea83081a66ff102e74fa7da7404280543c69 by @zlant.

Example: https://zlant.github.io/parking-lanes/#19/52.47398/13.44268