Storing cache in /tmp is not ideal since it will be wiped on system restarts, as such I'm proposing we move it to ~/.cache as per Deans suggestion.

EDIT: We might also consider defaulting to ~/Library/Caches on macOS, otherwise XDG_CACHE_DIR if set. If there's an equivalent on Windows, consider using that.

cacheDir defaults to /tmp/ on my system. We should probably change that to not use /tmp at all and instead use ~/.cache so we're not dumping 300MB into RAM on startup

Originally posted by @deansheather in #2533 (comment)