some big change using state machine

lib/ota/ota.h

@@ -1,9 +1,9 @@
 #pragma once
-#include <string>
+#include <string_view>
 
 class OTAHandler {
 public:
-    OTAHandler(std::string hostname);
+    OTAHandler(std::string_view hostname);
 
     void poll();
 };