Clean up /run/ at startup and move the directory creation logic to each service

scripts/service/sshd/run

@@ -2,5 +2,9 @@
 
 set -eu
 
+if [ ! -d /run/sshd/ ]; then
+	install -m 755 -o root -g root -d /run/sshd/
+fi
+
 exec 2>&1
 exec /usr/sbin/sshd -D