Provide better defaults for Roster cache

The username2roster cache was use the Openfire defaults of 256k/6hrs
which is not optimal for a base installation. This sets the default max
size to 1M and set the expiry to 30 minutes.

src/java/org/jivesoftware/util/cache/CacheFactory.java

@@ -152,6 +152,8 @@ public class CacheFactory {
         cacheProps.put("cache.lockOutCache.maxLifetime", JiveConstants.MINUTE * 15);
         cacheProps.put("cache.groupMeta.size", 512 * 1024l);
         cacheProps.put("cache.groupMeta.maxLifetime", JiveConstants.MINUTE * 15);
+        cacheProps.put("cache.username2roster.size", 1024 * 1024l);
+        cacheProps.put("cache.username2roster.maxLifetime", JiveConstants.MINUTE * 30);
         cacheProps.put("cache.javascript.size", 128 * 1024l);
         cacheProps.put("cache.javascript.maxLifetime", 3600 * 24 * 10l);
         cacheProps.put("cache.ldap.size", 512 * 1024l);