logger: remove journald support

It was only used by the removed startsubsys mode.

Signed-off-by: Nicola Murino <nicola.murino@gmail.com>

Author: drakkan

go.mod

@@ -106,7 +106,6 @@ require (
 	github.com/cenkalti/backoff/v5 v5.0.3 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/cncf/xds/go v0.0.0-20251210132809-ee656c7534f5 // indirect
-	github.com/coreos/go-systemd/v22 v22.6.0 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.7 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/envoyproxy/go-control-plane/envoy v1.36.0 // indirect

go.sum

@@ -115,8 +115,6 @@ github.com/cockroachdb/cockroach-go/v2 v2.4.3/go.mod h1:9U179XbCx4qFWtNhc7BiWLPf
 github.com/coreos/go-oidc/v3 v3.17.0 h1:hWBGaQfbi0iVviX4ibC7bk8OKT5qNr4klBaCHVNvehc=
 github.com/coreos/go-oidc/v3 v3.17.0/go.mod h1:wqPbKFrVnE90vty060SB40FCJ8fTHTxSwyXJqZH+sI8=
 github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
-github.com/coreos/go-systemd/v22 v22.6.0 h1:aGVa/v8B7hpb0TKl0MWoAavPDmHvobFe5R5zn0bCJWo=
-github.com/coreos/go-systemd/v22 v22.6.0/go.mod h1:iG+pp635Fo7ZmV/j14KUcmEyWF+0X7Lua8rrTWzYgWU=
 github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
 github.com/cpuguy83/go-md2man/v2 v2.0.7 h1:zbFlGlXEAKlwXpmvle3d8Oe3YnkKIK4xSRTd3sHPnBo=
 github.com/cpuguy83/go-md2man/v2 v2.0.7/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=