[collectd 6] Initial implementation for epics plugin #1256

Job	Run time
experimental (debian_unstable, --enable-compatibility-mode)	3m 58s
build (debian12, --enable-compatibility-mode)	3m 8s
experimental (fedora_main, --enable-compatibility-mode)	2m 27s
build (debian11, --enable-compatibility-mode)	2m 56s
experimental (debian_unstable, --enable-compatibility-mode --disable-dpdkstat --disable-dpdkevent...	3m 48s
experimental (fedora_main, --enable-compatibility-mode --disable-dpdkstat --disable-dpdkevents --...	2m 14s
build (debian10, --enable-compatibility-mode)	2m 57s
build (ubuntu23.10, --enable-compatibility-mode)	2m 38s
build (ubuntu22.04, --enable-compatibility-mode)	2m 38s
build (ubuntu20.04, --enable-compatibility-mode)	2m 50s
build (centos9, --enable-compatibility-mode)	3m 16s
build (fedora39, --enable-compatibility-mode)	2m 19s
build (fedora38, --enable-compatibility-mode)	2m 18s
build (debian12, --enable-compatibility-mode --enable-debug)	3m 4s
build (debian12, --enable-compatibility-mode CC=clang CXX=clang++, -gdwarf-4)	3m 14s
	43m 45s

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