make update message adjustable by provider

src/Env.cpp

@@ -0,0 +1,20 @@
+#include "Env.h"
+#include <optional>
+
+std::optional<std::string> Env::Get(Env::Key key) {
+    auto StrKey = ToString(key);
+    auto Value = std::getenv(StrKey.data());
+    if (!Value || std::string_view(Value).empty()) {
+        return std::nullopt;
+    }
+    return Value;
+}
+
+std::string_view Env::ToString(Env::Key key) {
+    switch (key) {
+    case Key::PROVIDER_UPDATE_MESSAGE:
+        return "BEAMMP_PROVIDER_UPDATE_MESSAGE";
+        break;
+    }
+    return "";
+}