When creating an archive starting from a subdirectory instead of the
root of a server's filesystem, the walker would treat the paths as if
they where relative to the parent of the subdirectory, instead of as
descendants of the subdirectory.
Fixes https://github.com/pterodactyl/panel/issues/5030
This wonderfully large commit replaces basically everything under the
`server/filesystem` package, re-implementing essentially everything.
This is related to
https://github.com/pterodactyl/wings/security/advisories/GHSA-494h-9924-xww9
If any vulnerabilities related to symlinks persist after this commit, I
will be very upset.
Signed-off-by: Matthew Penner <me@matthewp.io>