docs: Added docs for Packet class and onPacket event

fix: Added missing sendToAll method

docs/defaultEvents/network/onPacket.md

@@ -0,0 +1,22 @@
+# `event` onPacket
+This event is triggered when new packet arrives from the client.
+
+Original: [onPacket](https://gothicmultiplayerteam.gitlab.io/docs/0.3.0/script-reference/server-events/network/onPacket/)
+
+## Parameters
+* `dict` **kwargs**:
+    * `int` **playerid**: the id of the player who sent the packet.
+    * `Packet` **packet**: data sended over network from client side.
+
+## Usage
+```python
+import g2o
+        
+@g2o.event('onPacket')
+def onPacketEvt(**kwargs):
+    data = kwargs['data']
+    message = data.readString()
+    
+    print(f'Got packet from {kwargs['playerid']} (bytes used {data.bytesUsed})')
+    print(f'Packet says: {message}')
+```