Add ability to load cover art from tar archive for BDM/HDD devices

[mystyq]

Pull Request checklist

Note: these are not necessarily requirements

• I reformatted the code with clang-format
• I checked to make sure my submission worked
• I am the author of submission or have permission from the original author
• Requires update of the PS2SDK or other dependencies
• Others (please specify below)

Pull Request description

A hard-coded tar archive file called art.tar can be placed into the ART directory (flattened images) to be loaded as cover art.

This PR introduces a way to avoid parsing through the many files on large populated devices and gives the user an option to load them from a single archive instead.

Currently only BDM is tested, HDD (untested). There could be improvements in the timing of when the tar file entries are loaded into memory and even hooking the game list cache and parsing only the headers for those art files to keep the memory footprint smaller. Boot time could be improved by caching the headers on first boot.

To give an idea for how fast this can be, here is a video describing the behavior: Click Here. This is on a fully populated 6TB 5400 RPM drive with a 1.4GB tar file with the full OPLM Art Archive (only the COV,BG,LGO images).

As this is my first major contribution to an open-source project of this nature, please understand that I am learning and I wish to make this the best effort I can. If there is anything I can improve please let me know so I can do so. Thanks guys/gals.