Fix new projects always being created with OpenGL

Only Vulkan is fully implemented for now, so OpenGL isn't available
in the project manager yet.

This also makes the rendering driver checks use lowercase names
everywhere for consistency.

platform/iphone/export/export_plugin.cpp

@@ -33,7 +33,7 @@
 void EditorExportPlatformIOS::get_preset_features(const Ref<EditorExportPreset> &p_preset, List<String> *r_features) {
 	String driver = ProjectSettings::get_singleton()->get("rendering/driver/driver_name");
 	r_features->push_back("pvrtc");
-	if (driver == "Vulkan") {
+	if (driver == "vulkan") {
 		// FIXME: Review if this is correct.
 		r_features->push_back("etc2");
 	}