UI: Make service settings use OK/Apply/Cancel

Currently service settings are updated in real time via the properties
view, which means that OK/Cancel/Apply have no effect.  This fixes that
by using the new type of properties view that operates only on settings
data, not an object.

obs/window-basic-main.cpp

@@ -326,6 +326,11 @@ bool OBSBasic::LoadService()
 {
 	const char *type;
 
+	if (service) {
+		obs_service_destroy(service);
+		service = nullptr;
+	}
+
 	char serviceJsonPath[512];
 	int ret = os_get_config_path(serviceJsonPath, sizeof(serviceJsonPath),
 			SERVICE_PATH);
@@ -658,7 +663,6 @@ void OBSBasic::SaveProject()
 	if (ret <= 0)
 		return;
 
-	SaveService();
 	Save(savePath);
 }
 
@@ -1330,6 +1334,13 @@ void OBSBasic::SetService(obs_service_t *newService)
 	}
 }
 
+bool OBSBasic::StreamingActive()
+{
+	if (!outputHandler)
+		return false;
+	return outputHandler->StreamingActive();
+}
+
 #ifdef _WIN32
 #define IS_WIN32 1
 #else
@@ -2237,8 +2248,6 @@ void OBSBasic::on_streamButton_clicked()
 	if (outputHandler->StreamingActive()) {
 		outputHandler->StopStreaming();
 	} else {
-		SaveService();
-
 		if (outputHandler->StartStreaming(service)) {
 			ui->streamButton->setEnabled(false);
 			ui->streamButton->setText(