feat: implement retreiving widgets

- display a bottom sheet with widgets
- open widgets in a browser
- fixes in .gitignore
- Windows UWP build files

Signed-off-by: TheOneWithTheBraid <the-one@with-the-braid.cf>

winuwp/runner_uwp/main.cpp

@@ -0,0 +1,30 @@
+
+#include <windows.h>
+
+#include "winrt/Windows.ApplicationModel.Core.h"
+#include "winrt/Windows.Foundation.h"
+#include <winrt/Windows.Foundation.Collections.h>
+#include <winrt/Windows.UI.ViewManagement.Core.h>
+#include <winrt/Windows.UI.ViewManagement.h>
+
+#include <memory>
+
+#include "flutter_frameworkview.cpp"
+
+struct App
+    : winrt::implements<
+          App, winrt::Windows::ApplicationModel::Core::IFrameworkViewSource> {
+  App() { view_ = winrt::make_self<FlutterFrameworkView>(); }
+
+  // |winrt::Windows::ApplicationModel::Core::IFrameworkViewSource|
+  winrt::Windows::ApplicationModel::Core::IFrameworkView CreateView() {
+    return view_.as<winrt::Windows::ApplicationModel::Core::IFrameworkView>();
+  }
+
+  winrt::com_ptr<FlutterFrameworkView> view_;
+};
+
+int __stdcall wWinMain(HINSTANCE, HINSTANCE, PWSTR, int) {
+  winrt::Windows::ApplicationModel::Core::CoreApplication::Run(
+      winrt::make<App>());
+}