udev: raise RLIMIT_NOFILE as high as we can

udev: raise RLIMIT_NOFILE as high as we can

We might need a lot of fds on large systems, hence raise RLIMIT_NOFILE
to what the service manager allows us, which is quite a lot these days.

udev already sets FORK_RLIMIT_NOFILE_SAFE when forking of chilren, thus
ensuring that forked off processes get their RLIMIT_NOFILE soft limit
reset to 1K for compat with crappy old select().

Replaces: #29298
Fixes: #28583