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/crypto/encrypted_message_data_test.go

@@ -0,0 +1,37 @@
+package crypto
+
+import (
+	"testing"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestEncryptedMessageData_Encode(t *testing.T) {
+	const padding = 16
+
+	paddingRequired := func(l int) int {
+		return padding + (padding - (l % padding))
+	}
+
+	d := EncryptedMessageData{
+		Salt:                   1034,
+		SeqNo:                  1,
+		MessageID:              3401235566,
+		SessionID:              2345512351,
+		MessageDataLen:         5,
+		MessageDataWithPadding: []byte{1, 2, 3, 100, 112},
+	}
+	b := new(bin.Buffer)
+	if err := d.Encode(b); err != nil {
+		t.Fatal(err)
+	}
+	b.Buf = append(b.Buf, make([]byte, paddingRequired(b.Len()))...)
+	decoded := EncryptedMessageData{}
+	if err := decoded.Decode(b); err != nil {
+		t.Fatal(err)
+	}
+	decoded.MessageDataWithPadding = decoded.MessageDataWithPadding[:decoded.MessageDataLen]
+	require.Equal(t, d, decoded)
+}