Checkstyle: Add 'WhitespaceAfter' check, fix some violations

src/main/java/fr/xephi/authme/data/QuickCommandsProtectionManager.java

@@ -48,7 +48,7 @@ public class QuickCommandsProtectionManager implements SettingsDependent, HasCle
      * @param player the player to process
      */
     public void processJoin(Player player) {
-        if(shouldSavePlayer(player)) {
+        if (shouldSavePlayer(player)) {
             setJoin(player.getName());
         }
     }

src/main/java/fr/xephi/authme/data/TempbanManager.java

@@ -104,7 +104,7 @@ public class TempbanManager implements SettingsDependent, HasCleanup {
             expires.setTime(newTime);
 
             bukkitService.scheduleSyncDelayedTask(() -> {
-                if(customCommand.isEmpty()) {
+                if (customCommand.isEmpty()) {
                     bukkitService.banIp(ip, reason, expires, "AuthMe");
                     player.kickPlayer(reason);
                 } else {