Deletion and archival of Maps and Collections

[HSZemi]

Users shall be able to:

• delete their own map / collection until 24h after it was created
• archive their own map / collection from that point onwards

A deleted map / collection is removed from the database, the files are deleted from the disk.
An archived map / collection is marked in the database, but the database contents and files remain.

An archived map is still accessible via the direct url and remains part of collections that it is in, but it does no longer show up in searches and cannot be added to collections anymore. An archived collection is still accessible via the direct url, but it does no longer show up in searches. Archived maps and collections display an info box about their status.

[HSZemi]

Removal/Archival is done, let's closes this until somebody needs actual deletion for users.