added strutil to verify urls

src/espstrutils.h

@@ -6,10 +6,15 @@
 // esp-idf includes
 #include <esp_sntp.h>
 
+// 3rdparty lib includes
+#include <tl/expected.hpp>
+
 namespace espcpputils {
 
 std::string toString(sntp_sync_mode_t val);
 
 void urldecode(char *dst, const char *src);
 
+tl::expected<void, std::string> urlverify(std::string_view str);
+
 } // namespace espcpputils