Added btn in project view to open in file manager

Closes #26

lib/main.dart

@@ -7,6 +7,7 @@ import "main_menu/main_menu.dart";
 import "main_menu/projects/projects_screen.dart";
 import "prefs.dart";
 import "project_view/close_project_button.dart";
+import "project_view/open_in_explorer_button.dart";
 import "project_view/project_view.dart";
 import "tech_app.dart";
 
@@ -61,7 +62,10 @@ class MyHomePage extends ConsumerWidget {
         title: Text(title),
         actions: [
           const Text("Version: $version\nBlueMap: $blueMapTag"),
-          if (projectDirectory != null) const CloseProjectButton(),
+          if (projectDirectory != null) ...[
+            const OpenInFileManagerButton(),
+            const CloseProjectButton(),
+          ]
         ],
       ),
       body: projectDirectory == null ? const MainMenu() : const ProjectView(),

lib/project_view/open_in_explorer_button.dart

@@ -0,0 +1,24 @@
+import "dart:io";
+
+import "package:flutter/material.dart";
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:url_launcher/url_launcher.dart";
+
+import "../main_menu/projects/projects_screen.dart";
+
+class OpenInFileManagerButton extends ConsumerWidget {
+  const OpenInFileManagerButton({super.key});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    return IconButton(
+      tooltip: "Open in file manager",
+      onPressed: () {
+        final Directory? projectDirectory = ref.read(openProjectProvider);
+        if (projectDirectory == null) return;
+        launchUrl(projectDirectory.uri);
+      },
+      icon: const Icon(Icons.folder_open),
+    );
+  }
+}