try shorter fragments and longer playlist for better cache performance

leftover/nginx.conf.template

@@ -81,8 +81,8 @@ rtmp {
             live on;
             hls on;
             hls_fragment_naming system;
-            hls_fragment 5;
-            hls_playlist_length 30;
+            hls_fragment 3;
+            hls_playlist_length 60;
             hls_path /opt/data/hls;
             hls_nested on;