collections could have an additional map for places of archives

[GVogeler]

request by Illuminierte Urkunden project:

1. users add cei:placeName/@key to the cei:archIdentifier
2. this references geolocation information from metada.geo (need for new functionality to automatically add this information via a call to geonames? => method to add entries to metadata.geo.public by users #980)
3. use these informations to create a map of archives from the collection (re-use the module to display cei:issued/cei:placeName on a map: see solution for display cei:issued/cei:placeNamegeoreference on map #914 ), accessible from the collection list