feat(reflect-cpp): Switched from glaze -> reflect cpp

A bug was discovered in glaze which prevented valid toml output. We have
switched to toml++ and reflect-cpp. The interface has remained the same
so this should not break any code

build-config/reflect-cpp/include/rfl/internal/has_flatten_fields.hpp

@@ -0,0 +1,31 @@
+#ifndef RFL_INTERNAL_HASFLATTENFIELDS_HPP_
+#define RFL_INTERNAL_HASFLATTENFIELDS_HPP_
+
+#include <type_traits>
+#include <utility>
+
+#include "../Tuple.hpp"
+#include "is_flatten_field.hpp"
+
+namespace rfl {
+namespace internal {
+
+template <class TupleType>
+constexpr bool has_flatten_fields() {
+  const auto is_true_for_one =
+      []<int _i>(std::integral_constant<int, _i>) -> bool {
+    using T = std::remove_cvref_t<tuple_element_t<_i, TupleType>>;
+    return is_flatten_field_v<T>;
+  };
+
+  return [&]<int... _is>(std::integer_sequence<int, _is...>) {
+    return (false || ... ||
+            is_true_for_one(std::integral_constant<int, _is>{}));
+  }
+  (std::make_integer_sequence<int, rfl::tuple_size_v<TupleType>>());
+}
+
+}  // namespace internal
+}  // namespace rfl
+
+#endif