Authentication check plus signin screen added to frontend

Frontend/patient_manager/linux/flutter/generated_plugin_registrant.cc

@@ -6,6 +6,14 @@
 
 #include "generated_plugin_registrant.h"
 
+#include <gtk/gtk_plugin.h>
+#include <url_launcher_linux/url_launcher_plugin.h>
 
 void fl_register_plugins(FlPluginRegistry* registry) {
+  g_autoptr(FlPluginRegistrar) gtk_registrar =
+      fl_plugin_registry_get_registrar_for_plugin(registry, "GtkPlugin");
+  gtk_plugin_register_with_registrar(gtk_registrar);
+  g_autoptr(FlPluginRegistrar) url_launcher_linux_registrar =
+      fl_plugin_registry_get_registrar_for_plugin(registry, "UrlLauncherPlugin");
+  url_launcher_plugin_register_with_registrar(url_launcher_linux_registrar);
 }

Frontend/patient_manager/linux/flutter/generated_plugins.cmake

@@ -3,6 +3,8 @@
 #
 
 list(APPEND FLUTTER_PLUGIN_LIST
+  gtk
+  url_launcher_linux
 )
 
 list(APPEND FLUTTER_FFI_PLUGIN_LIST