Vidi (List Component)

It should be possible to group a number of records in collections (as outlined in the wireframes).

As for the technical implementation, this is how it should be:

- a new interface for collection handling in t3lib/interfaces/ (to be defined while implementing the default collection handler and seeing which methods make sense)
- a default implementation of the collection handling interface by vidi, which works with database tables out of the box

The default database-based collection handler of vidi should take the following configuration arguments in the ModuleLoader:

- which collection handler to use (it must implement the collection interface from t3lib/interface/
- database table name (this would be "sys_file_collection" in the case of the Media module)
- the field name to store the related uids into (internally it should use t3lib_loaddbgroup for the relation handling, so it works with whatever TCA config)
- the sorting field

Note the difference between the Media listing and the File listing:
- media listing is based entirely on sys_file records which have proper UIDs and are just normal database records in total. Here the default collection handling can be used.
- file listing is based on accessing the storage layer directly and here we deal with t3lib_file_Domain_Model_File objects. Here, a custom collection handler will be necessary if one would want collection handling here as well, but it is not necessary for us. Collection handling can rely on sys_file records to be present and only work in the media module.