add openfiles-max and kern.maxfiles settings for OpenBSD
https://trac.torproject.org/projects/tor/wiki/TorRelayGuide/OpenBSD
Cover the following settings:
- openfiles-max
- kern.maxfiles
ref #26619 (moved)
https://trac.torproject.org/projects/tor/wiki/TorRelayGuide/OpenBSD
Cover the following settings:
ref #26619 (moved)