OPNSense/core fe34833src/etc/inc system.inc

system: stop using a lock around resolv.conf handling #2267

This might kill a bit of delay in function use by doing an atomic
move to update resolv.conf.  Even if several instances are running
at the same time the contents of the file will be the same now.

I don't expect issues with the DNS route updates either: even if
they are removed or added twice, they will always end up being there.

(cherry picked from commit 5f4315c40ceeb6a9235cdaa4e5d758b777f72b1f)
DeltaFile
+4-5src/etc/inc/system.inc
+4-51 files

UnifiedSplitRaw