Automatically hide spots on gas stations deleted from OSM

[bopjesvla]

increasingly many spots are outdated

• get deleted gas/service stations as in https://help.openstreetmap.org/questions/50707/locating-deleted-items
• make sure the gas station has no positive reviews one month after the deletion date (i.e. trust our reviewers over osm)
• hide reviews by default (filter: hide reviews on structures that no longer exist)