Add BR systemd (no longer a dependency of systemd-devel)

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This merge request is automatically copied from !1475 (merged) from branch https://source.coderefinery.org/ellert/arc/-/tree/br-systemd orginally made by @ellert
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In the latest systemd package in Fedora 37 and rawhide systemd-devel no longer depends in systemd. Add BR systemd, since the build requires both systemd (for the rpm macros) and systemd-devel (for the headers and library .so link).