e2ee. (#226)

* chore: e2ee.

* update.

* update.

* update.

* update.

* chore: Use feat/frame-encryption branch of flutter-webrtc.

* chore: Add E2EEKEY defines for dart environment, and e2ee switch.

* Add encodedInsertableStreams to RTCConfiguration.

* update.

* feat: Add e2ee indicator for Participant.

* feat: add e2ee worker js for flutter web.

* dart format.

* remove unused file.

* fix flutter analyze .

* update.

* update.

* add: indicate for decryption failure, and string key.

* remove .lock files.

* update.

* update.

* update e2ee.worker for web.

* feat: support setCodecPreferences.

* state TrackE2EEStateEvent.

* fix wrong import interface from dart_webrtc.

* update.

* update.

* update.

* update.

* update pubspec.lock.

* chore: update protocol and add EncryptionType for Participant.

* Update lib/src/e2ee/options.dart

Co-authored-by: Théo Monnom <theo.monnom@outlook.com>

* fix typo.

* revert changes for internal import.

* Add _cleanUp() for previous room.

* Add e2ee supports detection method for native/web.

* Remove redundant overriding methods.

* dart format.

* Add e2ee.worker code and deployment docs.

* chore: remove duplicate words.

* chore: using Pbkdf2 derive the key.

* Update pubspec.yaml

* fix e2ee for safari.

* fix key length.

* update e2ee.worker.dart.js.

* fix.

* update proto.

* update.

* chore: add simulate for rachetKey.

* update.

* chore: key ratchet for flutter web.

* update.

* update.

* update.

* chore: key ratchet export for web.

* bump version for xframeworks.

* update.

* chore: some changes for key safety ratcheting.

* update.

* fix typo.

* update.

* rename.

* magic bytes for web.

* bump version for flutter-webrtc.

* fix analyzer.

---------

Co-authored-by: Théo Monnom <theo.monnom@outlook.com>

pubspec.lock

@@ -129,6 +129,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.0.2"
+  cryptography:
+    dependency: "direct main"
+    description:
+      name: cryptography
+      sha256: e0e37f79665cd5c86e8897f9abe1accfe813c0cc5299dab22256e22fddc1fef8
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.5"
   dart_style:
     dependency: transitive
     description:
@@ -227,11 +235,12 @@ packages:
   flutter_webrtc:
     dependency: "direct main"
     description:
-      name: flutter_webrtc
-      sha256: f8904369f3ad57945a797481bf079c281f4944ad4635e9d412529141d81c9c76
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.9.25"
+      path: "."
+      ref: "feat/frame-encryption"
+      resolved-ref: abb6aba36434fa3a30ce5c56b6c521acb83b1139
+      url: "https://github.com/flutter-webrtc/flutter-webrtc.git"
+    source: git
+    version: "0.9.20"
   flutter_window_close:
     dependency: "direct main"
     description: