move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/mtproto/handle_message.go

@@ -0,0 +1,44 @@
+package mtproto
+
+import (
+	"github.com/go-faster/errors"
+	"go.uber.org/zap"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/mt"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto"
+)
+
+func (c *Conn) handleMessage(msgID int64, b *bin.Buffer) error {
+	id, err := b.PeekID()
+	if err != nil {
+		// Empty body.
+		return errors.Wrap(err, "peek message type")
+	}
+
+	c.logWithBuffer(b).Debug("Handle message", zap.Int64("msg_id", msgID))
+
+	switch id {
+	case mt.NewSessionCreatedTypeID:
+		return c.handleSessionCreated(b)
+	case mt.BadMsgNotificationTypeID, mt.BadServerSaltTypeID:
+		return c.handleBadMsg(b)
+	case mt.FutureSaltsTypeID:
+		return c.handleFutureSalts(b)
+	case proto.MessageContainerTypeID:
+		return c.handleContainer(msgID, b)
+	case proto.ResultTypeID:
+		return c.handleResult(b)
+	case mt.PongTypeID:
+		return c.handlePong(b)
+	case mt.MsgsAckTypeID:
+		return c.handleAck(b)
+	case proto.GZIPTypeID:
+		return c.handleGZIP(msgID, b)
+	case mt.MsgDetailedInfoTypeID,
+		mt.MsgNewDetailedInfoTypeID:
+		return nil
+	default:
+		return c.handler.OnMessage(b)
+	}
+}