Resource expiraton

[jstoone]

About

As a feature a user can enable expiration on their resource. Once expired a resource should be deleted and any associated files as well.

The following two types of expiration should be available:

• Time-based expiration (Time-based expiration #5)
• "First view" expiration (Expire after first view #6)

Cron-based logic should be implemented in the following intervals:

• Cron runs once pr. minute "soft deletes" resource
• Cron runs once pr. hour and removes resource
• Cron runs once pr. hour and removes orphan files from database and disk