Increase max files for pfs@mhs-ics

The archiver opens at least one file per MHS keyword/table. This is now above the default limit of 1024. So that the launch-on-boot mechanism works, that limit needs to be increased globally. A quick google suggests adding something like:

pfs               soft    nofile          10240
pfs               hard    nofile         10240

to /etc/security/limits.conf is the trick.

For the current failure, we will restart it manually with increased limits. The data between 2023-10-19T15 and now is not in the archiver. If there are certain keywords which are badly wanted we can recover them from the /data/logs/tron/ logs, but do not plan on doing that if not needed.