Make packet charset configurable

Better support for different language clients such as Thai or Korean

src/main/java/net/packet/ByteBufInPacket.java

@@ -1,5 +1,6 @@
 package net.packet;
 
+import constants.string.CharsetConstants;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 
@@ -49,7 +50,7 @@ public class ByteBufInPacket implements InPacket {
         short length = readShort();
         byte[] stringBytes = new byte[length];
         byteBuf.readBytes(stringBytes);
-        return new String(stringBytes, STRING_CHARSET);
+        return new String(stringBytes, CharsetConstants.PACKET_CHARSET);
     }
 
     @Override

src/main/java/net/packet/ByteBufOutPacket.java

@@ -1,5 +1,6 @@
 package net.packet;
 
+import constants.string.CharsetConstants;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
@@ -77,12 +78,12 @@ public class ByteBufOutPacket implements OutPacket {
     @Override
     public void writeString(String value) {
         writeShort((short) value.length());
-        writeBytes(value.getBytes(STRING_CHARSET));
+        writeBytes(value.getBytes(CharsetConstants.PACKET_CHARSET));
     }
 
     @Override
     public void writeFixedString(String value) {
-        writeBytes(value.getBytes(STRING_CHARSET));
+        writeBytes(value.getBytes(CharsetConstants.PACKET_CHARSET));
     }
 
     @Override

src/main/java/net/packet/Packet.java

@@ -1,10 +1,5 @@
 package net.packet;
 
-import java.nio.charset.Charset;
-import java.nio.charset.StandardCharsets;
-
 public interface Packet {
-    Charset STRING_CHARSET = StandardCharsets.US_ASCII;
-
     byte[] getBytes();
 }