All packet creating methods now create Packet instead of byte[]

This commit got way too big...
- Remove deprecated methods for sending packets
- Favor OutPacket & Packet over MaplePacketLittleEndianWriter, LittleEndianWriter, and byte array
- Split up some packet creating methods into separate classes

src/test/java/net/packet/ByteBufOutPacketTest.java

@@ -176,9 +176,9 @@ class ByteBufOutPacketTest {
     }
 
     @Test
-    void writePoint() {
+    void writePosition() {
         final Point writtenPoint = new Point(23, 42);
-        outPacket.writePoint(writtenPoint);
+        outPacket.writePos(writtenPoint);
 
         ByteBuf wrapped = wrapExplicitlyWrittenBytes(outPacket);
         short readX = wrapped.readShortLE();