Fix #16: SSL pinning in all 4 Flutter apps

- Created ssl_pinning.dart with SHA-256 DER hash pinning for intaleq.xyz and siromove.com
- Replaced http.post/http.get with pinned client in all CRUD classes
- Added crypto dependency to siro_admin and siro_driver pubspec

siro_service/lib/controller/functions/crud.dart

@@ -15,9 +15,11 @@ import 'package:siro_service/main.dart';
 import 'package:siro_service/print.dart';
 
 import '../../constant/api_key.dart';
+import 'ssl_pinning.dart';
 
 class CRUD {
   static String? _appSignature;
+  final _client = SslPinning.createPinnedClient();
 
   static String _lastErrorSignature = '';
   static DateTime _lastErrorTimestamp = DateTime(2000);
@@ -337,7 +339,7 @@ class CRUD {
     required String channelName,
     required String uid,
   }) async {
-    var res = await http.get(
+    var res = await _client.get(
         Uri.parse(
             'https://orca-app-b2i85.ondigitalocean.app/token?channelName=$channelName'),
         headers: {'Authorization': 'Bearer '});
@@ -371,7 +373,7 @@ class CRUD {
       ],
       "temperature": 0.9
     });
-    var response = await http.post(url, body: data, headers: headers);
+    var response = await _client.post(url, body: data, headers: headers);
 
     if (response.statusCode == 200) {
       return response.body;