Use journald in systemd environments

[dervomsee]

Jounald is more efficent, managing the log data.
I my opinion it would make sense, removing these lines in systemd/journald environments and stdout the log to journald.

AdGuardHome/internal/home/service.go

Lines 425 to 426 in 2e0f6e5

	StandardOutput=file:/var/log/{{.Name}}.out
	StandardError=file:/var/log/{{.Name}}.err