GameSBFL replication package: build and recording caches

Build and recording caches for an anonymous replication package under double-anonymous peer review. The archives hold every mutant build and every replay recording of the reference run, so the experiment can be re-run without compiling the games or replaying the tapes (Linux x86-64, Ubuntu 24.04). Use them with the controller package, following its README section "The whole experiment, from the caches": pack_caches.py verify checks the archives against caches.manifest.json, and pack_caches.py unpack restores them (19 GB). games.zip holds the source of the game binaries: patches against public upstream commits and the script that rebuilds every mutant from them (see its README). Licenses: the game binaries in build_cache--*.tar.zst keep the licenses of their games: GPL-3.0 for Super Tux, Super Tux Kart and Witch Blast; LGPL-2.1-or-later / GPL-3.0 for FreeMiner; MIT for Asteroids. So does the game art and audio in the recordings (Witch Blast's art is CC BY-NC-SA). games.zip states its own licenses in its LICENSE.md. Everything else is CC BY 4.0.