triggers panel multi-ds supoort: refactor

src/panel-triggers/migrations.js

@@ -0,0 +1,15 @@
+export function migratePanelSchema(panel) {
+  const schemaVersion = getSchemaVersion(panel);
+  switch (schemaVersion) {
+    case 1:
+      panel.datasources = [panel.datasource];
+      panel.targets[panel.datasources[0]] = panel.triggers;
+      break;
+  }
+
+  return panel;
+}
+
+function getSchemaVersion(panel) {
+  return panel.schemaVersion || 1;
+}