Support AGH without DHCP server

lib/screens/settings/dhcp/dhcp_main_button.dart

@@ -0,0 +1,76 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+
+import 'package:adguard_home_manager/models/dhcp.dart';
+
+class DhcpMainButton extends StatelessWidget {
+  final NetworkInterface? selectedInterface;
+  final bool enabled;
+  final void Function(bool) setEnabled;
+
+  const DhcpMainButton({
+    super.key,
+    required this.selectedInterface,
+    required this.enabled,
+    required this.setEnabled,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: const EdgeInsets.only(
+        top: 10,
+        left: 16, 
+        right: 16
+      ),
+      child: Material(
+        color: Theme.of(context).colorScheme.primary.withOpacity(0.1),
+        borderRadius: BorderRadius.circular(28),
+        child: InkWell(
+          onTap: selectedInterface != null
+            ? () => setEnabled(!enabled)
+            : null,
+          borderRadius: BorderRadius.circular(28),
+          child: Padding(
+            padding: const EdgeInsets.symmetric(
+              horizontal: 20,
+              vertical: 12
+            ),
+            child: Row(
+              mainAxisAlignment: MainAxisAlignment.spaceBetween,
+              children: [
+                Column(
+                  crossAxisAlignment: CrossAxisAlignment.start,
+                  children: [
+                    Text(
+                      AppLocalizations.of(context)!.enableDhcpServer,
+                      style: TextStyle(
+                        fontSize: 16,
+                        color: Theme.of(context).colorScheme.onSurface
+                      ),
+                    ),
+                    if (selectedInterface != null) ...[
+                      Text(
+                        selectedInterface!.name,
+                        style: TextStyle(
+                          fontSize: 14,
+                          color: Theme.of(context).listTileTheme.textColor
+                        ),
+                      )
+                    ]
+                  ],
+                ),
+                Switch(
+                  value: enabled, 
+                  onChanged: selectedInterface != null
+                    ? (value) => setEnabled(value)
+                    : null,
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}