Dashboard node import and render in browser (#2374)

esphome/components/dashboard_import/dashboard_import.cpp

@@ -0,0 +1,12 @@
+#include "dashboard_import.h"
+
+namespace esphome {
+namespace dashboard_import {
+
+static std::string g_package_import_url;  // NOLINT
+
+std::string get_package_import_url() { return g_package_import_url; }
+void set_package_import_url(std::string url) { g_package_import_url = std::move(url); }
+
+}  // namespace dashboard_import
+}  // namespace esphome