final touches for labels

[adam-ce]

• size should depend on importance
• fix float inaccuracy wiggling by anchoring it to a tile and then compute a delta to the camera position
• link to wikipedia, if possible
• make phone number of huts callable on android
• pack address into one attribute field
• tickbox for webcams is not always working
• find a better symbol for the webcams and huts
• show hut name only when zoomed in, but always show symbol
• huts and webcams should be shown above ground similar to cities.
• fine tune importance / visibility of cities and mountains.
• in top view, labels should be well above the terrain, otherwise they get occluded
• Adlersruhe peak is missing -> should be shown when zoomed in -> LD: "just check adlersruhe is in osm dataset but it doesn't have any elevation stored -> we therefore aren't using this at all (fix would be to change the first query of peaks.sql where we are removing peaks that have no elevation set and give the importance_metric some value (e.g. 0)"
• Erzherzog Johann Huette is missing -> LD: "hm the adlersruhe hut is also present in the dataset but it is neither a
  planet_osm_point."tourism" = alpine_hut or wilderness_hut (not sure how it is classified)"
• remove importance for webcams and huts -> LD: "this will most likely be done in the webcams.sql / cottages.sql"

[LucasDworschak]

the commit e949530 should fix a few of the named issues.
namely:

• size should depend on importance
• link to wikipedia, if possible (also linked to wikidata)
• make phone number of huts callable on android
• pack address into one attribute field
• huts and webcams should be shown above ground similar to cities.