Add envoy support to solar logger

include/solar/logger/envoydata.hpp

@@ -0,0 +1,14 @@
+#pragma once
+#include <optional>
+#include <string>
+
+struct EnvoyData
+{
+    std::string type;
+    std::int32_t activeCount;
+    std::int64_t readingTime;
+    std::int32_t wNow;
+    std::int64_t whLifetime;
+
+    static std::optional<EnvoyData> ParseJson(std::string const & json);
+};