feat: add debug screen

lib/screens/debug_screen.dart

+import 'package:easy_localization/easy_localization.dart';
+import 'package:gecko/globals.dart';
+import 'package:flutter/material.dart';
+import 'package:gecko/providers/substrate_sdk.dart';
+import 'package:provider/provider.dart';
+
+class DebugScreen extends StatelessWidget {
+  const DebugScreen({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    final sub = Provider.of<SubstrateSdk>(context);
+
+    return Scaffold(
+        backgroundColor: backgroundColor,
+        appBar: AppBar(
+            toolbarHeight: 60 * ratio,
+            title: const SizedBox(
+              height: 22,
+              child: Text('Debug screen'),
+            )),
+        body: SafeArea(
+          child: Column(children: <Widget>[
+            const SizedBox(height: 40),
+            Center(
+              child: Column(
+                children: [
+                  Text(
+                    'node: ${sub.getConnectedEndpoint()}',
+                    style: TextStyle(fontSize: 15, color: Colors.grey[700]),
+                  ),
+                  const SizedBox(height: 15),
+                  Text(
+                    'blockN'.tr(args: [
+                      sub.blocNumber.toString()
+                    ]), //'bloc N°${sub.blocNumber}',
+                    style: TextStyle(fontSize: 15, color: Colors.grey[700]),
+                  ),
+                  const SizedBox(height: 20),
+                  SizedBox(
+                    height: 60,
+                    width: 250,
+                    child: ElevatedButton(
+                      style: ElevatedButton.styleFrom(
+                        foregroundColor: Colors.white, elevation: 4,
+                        backgroundColor: orangeC, // foreground
+                      ),
+                      onPressed: () async => await sub.spawnBlock(),
+                      child: const Text(
+                        'Spawn a bloc',
+                        style: TextStyle(
+                            fontSize: 20, fontWeight: FontWeight.w600),
+                      ),
+                    ),
+                  ),
+                ],
+              ),
+            ),
+          ]),
+        ));
+  }
+}