refactor: Move data classes into their own files

.gitlint

@@ -5,6 +5,6 @@ line-length=72
 [title-trailing-punctuation]
 [title-hard-tab]
 [title-match-regex]
-regex=^(feat|fix|test|release|chore|security|docs):.*$
+regex=^(feat|fix|test|release|chore|security|docs|refactor):.*$
 [body-trailing-whitespace]
 [body-first-line-empty]

lib/omemo_dart.dart

@@ -7,6 +7,8 @@ export 'src/helpers.dart';
 export 'src/keys.dart';
 export 'src/omemo/bundle.dart';
 export 'src/omemo/device.dart';
+export 'src/omemo/encrypted_key.dart';
+export 'src/omemo/encryption_result.dart';
 export 'src/omemo/fingerprint.dart';
 export 'src/omemo/sessionmanager.dart';
 export 'src/x3dh/x3dh.dart';

lib/src/omemo/encrypted_key.dart

@@ -0,0 +1,13 @@
+import 'package:meta/meta.dart';
+
+/// EncryptedKey is the intermediary format of a <key /> element in the OMEMO message's
+/// <keys /> header.
+@immutable
+class EncryptedKey {
+
+  const EncryptedKey(this.jid, this.rid, this.value, this.kex);
+  final String jid;
+  final int rid;
+  final String value;
+  final bool kex;
+}

lib/src/omemo/encryption_result.dart

@@ -0,0 +1,15 @@
+import 'package:meta/meta.dart';
+import 'package:omemo_dart/src/omemo/encrypted_key.dart';
+
+@immutable
+class EncryptionResult {
+
+  const EncryptionResult(this.ciphertext, this.encryptedKeys);
+  
+  /// The actual message that was encrypted
+  final List<int>? ciphertext;
+
+  /// Mapping of the device Id to the key for decrypting ciphertext, encrypted
+  /// for the ratchet with said device Id
+  final List<EncryptedKey> encryptedKeys;
+}

lib/src/omemo/sessionmanager.dart

@@ -12,6 +12,8 @@ import 'package:omemo_dart/src/helpers.dart';
 import 'package:omemo_dart/src/keys.dart';
 import 'package:omemo_dart/src/omemo/bundle.dart';
 import 'package:omemo_dart/src/omemo/device.dart';
+import 'package:omemo_dart/src/omemo/encrypted_key.dart';
+import 'package:omemo_dart/src/omemo/encryption_result.dart';
 import 'package:omemo_dart/src/omemo/fingerprint.dart';
 import 'package:omemo_dart/src/omemo/ratchet_map_key.dart';
 import 'package:omemo_dart/src/protobuf/omemo_authenticated_message.dart';
@@ -22,30 +24,6 @@ import 'package:synchronized/synchronized.dart';
 
 /// The info used for when encrypting the AES key for the actual payload.
 const omemoPayloadInfoString = 'OMEMO Payload';
-@immutable
-class EncryptionResult {
-
-  const EncryptionResult(this.ciphertext, this.encryptedKeys);
-  
-  /// The actual message that was encrypted
-  final List<int>? ciphertext;
-
-  /// Mapping of the device Id to the key for decrypting ciphertext, encrypted
-  /// for the ratchet with said device Id
-  final List<EncryptedKey> encryptedKeys;
-}
-
-/// EncryptedKey is the intermediary format of a <key /> element in the OMEMO message's
-/// <keys /> header.
-@immutable
-class EncryptedKey {
-
-  const EncryptedKey(this.jid, this.rid, this.value, this.kex);
-  final String jid;
-  final int rid;
-  final String value;
-  final bool kex;
-}
 
 class OmemoSessionManager {