examples, oneshot services rework

Signed-off-by: fbt <fbt@fleshless.org>

examples/services/nginx

@@ -0,0 +1,8 @@
+#!/usr/bin/env ssm
+
+service_respawn = on-failure
+service_command = /usr/bin/nginx
+service_pidfile = /run/nginx.pid
+
+# Do not reload the service if the config test fails.
+pre_reload() { "$service_command" -t "$@"; }