Add some leisure POIs

Some nodes (and areas) from the OSM [leisure](https://wiki.openstreetmap.org/wiki/Key:leisure) primary key would be useful to display, I'm mostly thinking of [park](https://wiki.openstreetmap.org/wiki/Tag:leisure%3Dpark) or [playground](https://wiki.openstreetmap.org/wiki/Tag:leisure%3Dplayground) but there might be others.