units: bump the RLIMIT_NOFILE soft limit for all services that access the journal

units: bump the RLIMIT_NOFILE soft limit for all services that access the journal

This updates the unit files of all our serviecs that deal with journal
stuff to use a higher RLIMIT_NOFILE soft limit by default. The new value
is the same as used for the new HIGH_RLIMIT_NOFILE we just added.

With this we ensure all code that access the journal has higher
RLIMIT_NOFILE. The code that runs as daemon via the unit files, the code
that is run from the user's command line via C code internal to the
relevant tools. In some cases this means we'll redundantly bump the
limits as there are tools run both from the command line and as service.