Use size, age, and view count to determine which albums should be deleted next

[4pr0n]

Current system deletes based on FIFO:

• https://github.com/4pr0n/rip/blob/master/python_cleanup.py

Viewing or ripping an album will reset the last-updated time to the current time.

This means least-recently-accessed albums will be deleted first.

Deletions occur when total size of all /rips/ gets above a threshold (currently 150GB).

Ideally:

• sets that were only accessed once should be considered deletable.
• Popular sets that haven't been view for a day or two should remain.