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/cipher_encrypt_test.go

@@ -0,0 +1,41 @@
+package crypto
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/testutil"
+)
+
+func TestEncrypt(t *testing.T) {
+	c := NewClientCipher(testutil.ZeroRand{})
+
+	var authKey Key
+	for i := 0; i < 256; i++ {
+		authKey[i] = byte(i)
+	}
+
+	// Testing vector from grammers.
+	msg, err := c.encryptMessage(
+		authKey.WithID(),
+		&bin.Buffer{Buf: []byte("Hello, world! This data should remain secure!")},
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	b := &bin.Buffer{}
+	if err := msg.Encode(b); err != nil {
+		t.Fatal(err)
+	}
+
+	expected := []byte{
+		50, 209, 88, 110, 164, 87, 223, 200, 168, 23, 41, 212, 109, 181, 64, 25, 162, 191, 215,
+		247, 68, 249, 185, 108, 79, 113, 108, 253, 196, 71, 125, 178, 162, 193, 95, 109, 219,
+		133, 35, 95, 185, 85, 47, 29, 132, 7, 198, 170, 234, 0, 204, 132, 76, 90, 27, 246, 172,
+		68, 183, 155, 94, 220, 42, 35, 134, 139, 61, 96, 115, 165, 144, 153, 44, 15, 41, 117,
+		36, 61, 86, 62, 161, 128, 210, 24, 238, 117, 124, 154,
+	}
+	require.Equal(t, expected, b.Buf)
+}