refactor: untangle lnd's macaroon encryption with AESCipher class (#3152)

tests/unit/test_crypto_aes.py

@@ -0,0 +1,20 @@
+import pytest
+
+from lnbits.utils.crypto import AESCipher
+
+
+@pytest.mark.anyio
+@pytest.mark.parametrize(
+    "key",
+    [
+        "normal_string",
+        b"normal_bytes",
+        b"hex_string".hex(),
+    ],
+)
+async def test_aes_encrypt_decrypt(key):
+    aes = AESCipher(key)
+    original_text = "Hello, World!"
+    encrypted_text = aes.encrypt(original_text.encode())
+    decrypted_text = aes.decrypt(encrypted_text)
+    assert original_text == decrypted_text