Consider packing the cache

[ydahhrk]

RPKI usage in on the rise, which means the cache might reach normal inode limits at some point.

By tarring Repository Publication Points and their contents, the entire cache can be preserved for a much smaller number of files.

rsync packing might also be feasible, by performing rsyncs on a mounted filesystem backed by a file. Depending on performance, this solution might in fact be usable on the entire cache.

Needs performance analysis.