reduce view- and simulation distance to improve performance

src/server.properties

@@ -53,7 +53,7 @@ resource-pack-sha1=
 server-ip=
 server-name=Unknown Server
 server-port=25565
-simulation-distance=10
+simulation-distance=8
 spawn-animals=true
 spawn-monsters=true
 spawn-npcs=true
@@ -61,5 +61,5 @@ spawn-protection=0
 sync-chunk-writes=true
 text-filtering-config=
 use-native-transport=true
-view-distance=10
+view-distance=8
 white-list=false