Keep vanetza-idf in obu-firmware, so a plain clone builds the firmware

obu-firmware builds against the vanetza-idf C-ITS library, which until now
came from the colleague's microbu-esp32c5 tree beside the repository and was
not tracked here, so a clone of this repository could not build the firmware
it ships. The library alone is now part of obu-firmware, as
obu-firmware/external/vanetza-idf: their external/vanetza-idf at commit
cf4b99f, unchanged (9775 files; see its PROVENANCE.md). CMake takes it from
there by default; -DVANETZA_IDF_DIR still points the build elsewhere.

The rest of the colleague's tree (their own VAM firmware, PKI tooling,
station-link Python tools, the V2X2MAP bridge) stays out of this repository
and gitignored; nothing is pushed to their repository. NOTES.md, docs/06,
TODO.md and the pcap verifier's usage line point at the new location.

obu-firmware/external/vanetza-idf/vanetza/common/object_container.hpp

@@ -0,0 +1,111 @@
+#ifndef OBJECT_CONTAINER_HPP_25SOHVUH
+#define OBJECT_CONTAINER_HPP_25SOHVUH
+
+#include <functional>
+#include <map>
+#include <memory>
+#include <typeindex>
+#include <type_traits>
+
+namespace vanetza
+{
+
+class ObjectContainer
+{
+private:
+    struct object_handle
+    {
+        template<typename T>
+        object_handle(std::unique_ptr<T> obj) :
+            object(obj.release()),
+            deleter([](void* ptr) { std::default_delete<T>()(static_cast<T*>(ptr)); })
+        {
+        }
+
+        ~object_handle() {
+            deleter(object);
+            object = nullptr;
+        }
+
+        void* object;
+        std::function<void(void*)> deleter;
+    };
+    using container_type = std::map<std::type_index, object_handle>;
+
+public:
+    ObjectContainer() = default;
+
+    // no copy
+    ObjectContainer(const ObjectContainer&) = delete;
+    ObjectContainer& operator=(const ObjectContainer&) = delete;
+
+    // allow move
+    ObjectContainer(ObjectContainer&&) = default;
+    ObjectContainer& operator=(ObjectContainer&&) = default;
+
+    bool empty() const { return m_container.empty(); }
+
+    std::size_t size() const { return m_container.size(); }
+
+    void clear() { m_container.clear(); }
+
+    template<typename T>
+    void erase()
+    {
+        m_container.erase(std::type_index(typeid(T)));
+    }
+
+    template<typename T>
+    T* find()
+    {
+        T* result = nullptr;
+        auto found = m_container.find(std::type_index(typeid(T)));
+        if (found != m_container.end()) {
+            result = static_cast<T*>(found->second.object);
+        }
+        return result;
+    }
+
+    template<typename T>
+    const T* find() const
+    {
+        const T* result = nullptr;
+        auto found = m_container.find(std::type_index(typeid(T)));
+        if (found != m_container.end()) {
+            result = static_cast<const T*>(found->second.object);
+        }
+        return result;
+    }
+
+    template<typename T>
+    bool insert(std::unique_ptr<T> obj)
+    {
+        static_assert(std::is_object<T>() && !std::is_const<T>(),
+                "Only non-const objects are supported by ObjectContainer");
+        return m_container.emplace(std::type_index(typeid(T)), std::move(obj)).second;
+    }
+
+    template<typename T>
+    T& get()
+    {
+        static_assert(std::is_default_constructible<T>(),
+                "Only default constructible types are accessible through ObjectContainer::get");
+        T* result = find<T>();
+        if (!result) {
+            std::unique_ptr<T> obj { new T() };
+            result = obj.get();
+            if (!insert(std::move(obj)))
+                result = nullptr;
+        }
+        assert(result);
+        return *result;
+    }
+
+private:
+    container_type m_container;
+};
+
+} // namespace vanetza
+
+#endif /* OBJECT_CONTAINER_HPP_25SOHVUH */
+