[Streaming] Implement a Logic File concept

Implement a logic file, which contains simple information on how to access separate chunks of the same "file".

When streaming, inputs can create several different chunks when buffering to the same file. These chunks are ordered, but not necessarily consumed in the same order (especially if one consumer fails and has to retry).

So, at least, we need logic to say what is the next available chunk and how many chunks we still have to read at any given time.

Investigate the dali/base/dadfs.cpp and ask Jake in case of doubts. The common area would probably be a good place to put the file in, and in the future, this logic file could end up replacing the current Dali super-file?