Add injectable ssl certs to baseline nginx instance too.

php/nginx/nginx.runit

@@ -1,3 +1,11 @@
 #!/usr/bin/env bash
+if [ -z "${SSL_CERTIFICATE}" ]; then
+  echo "No certificate set, using defaults"
+else
+  echo "Setting /certs/example.crt and /certs/example.key"
+  echo "${SSL_CERTIFICATE}}" > /certs/example.crt
+  echo "${SSL_CERTIFICATE_KEY}" > /certs/example.key
+fi
+
 /usr/sbin/nginx