CW-319-Wallet-Seed-keys-URI-QR-code (#831)

* wallet QR code on Wallet/Seed screen

* fix restore height for new wallet

* fix height parameter

* fix currenHeight and HeightByDate for haven

* update configure.dart

* fix coments

* minor fix

lib/src/screens/wallet_keys/wallet_keys_page.dart

@@ -1,6 +1,7 @@
 import 'package:auto_size_text/auto_size_text.dart';
 import 'package:cake_wallet/src/widgets/section_divider.dart';
 import 'package:cake_wallet/utils/show_bar.dart';
+import 'package:device_display_brightness/device_display_brightness.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/services.dart';
@@ -9,6 +10,7 @@ import 'package:cake_wallet/generated/i18n.dart';
 import 'package:cake_wallet/src/screens/base_page.dart';
 import 'package:cake_wallet/src/widgets/list_row.dart';
 import 'package:cake_wallet/view_model/wallet_keys_view_model.dart';
+import 'package:cake_wallet/routes.dart';
 
 class WalletKeysPage extends BasePage {
   WalletKeysPage(this.walletKeysViewModel);
@@ -18,6 +20,32 @@ class WalletKeysPage extends BasePage {
 
   final WalletKeysViewModel walletKeysViewModel;
 
+  @override
+  Widget trailing(BuildContext context) => IconButton(
+      onPressed: () async {
+        // Get the current brightness:
+        final double brightness = await DeviceDisplayBrightness.getBrightness();
+
+        // ignore: unawaited_futures
+        DeviceDisplayBrightness.setBrightness(1.0);
+        await Navigator.pushNamed(
+          context,
+          Routes.fullscreenQR,
+          arguments: {
+            'qrData': (await walletKeysViewModel.url).toString(),
+            'isLight': true,
+          },
+        );
+        // ignore: unawaited_futures
+        DeviceDisplayBrightness.setBrightness(brightness);
+      },
+      splashColor: Colors.transparent,
+      highlightColor: Colors.transparent,
+      hoverColor: Colors.transparent,
+      icon: Image.asset(
+        'assets/images/qr_code_icon.png',
+      ));
+
   @override
   Widget body(BuildContext context) {
     return Column(