Keep the colleague's microbu-esp32c5 tree in this repository

obu-firmware builds against vanetza-idf from microbu-esp32c5/external, but
that tree was gitignored, so a clone of this repository could not build the
firmware it ships. It is now committed here as ordinary files in its own
folder, microbu-esp32c5/: the colleague's commit cf4b99f plus the V2X2MAP
bridge's signature verification (--trust) used on the bench. Nothing is
fetched from or pushed to the colleague's repository; this repository and
its remotes carry everything. The folder's own .gitignore keeps build output,
downloaded components and private key material out, as it did there; the
committed file set is identical to that repository's tracked files.

The ESP32-C5 is still flashed from obu-firmware/, which only takes
vanetza-idf from microbu-esp32c5/, so the two stay separate folders.
FLASHING.md says how to take a newer version of the colleague's tree (copy
it over the folder, rebuild, test, commit).

microbu-esp32c5/external/vanetza-idf/tools/socktap/cam_application.hpp

@@ -0,0 +1,32 @@
+#ifndef CAM_APPLICATION_HPP_EUIC2VFR
+#define CAM_APPLICATION_HPP_EUIC2VFR
+
+#include "application.hpp"
+#include <vanetza/common/clock.hpp>
+#include <vanetza/common/position_provider.hpp>
+#include <vanetza/common/runtime.hpp>
+
+class CamApplication : public Application
+{
+public:
+    CamApplication(vanetza::PositionProvider& positioning, vanetza::Runtime& rt);
+    PortType port() override;
+    void indicate(const DataIndication&, UpPacketPtr) override;
+    void set_interval(vanetza::Clock::duration);
+    void set_station_id(std::uint32_t station_id);
+    void print_received_message(bool flag);
+    void print_generated_message(bool flag);
+
+private:
+    void schedule_timer();
+    void on_timer(vanetza::Clock::time_point);
+
+    vanetza::PositionProvider& positioning_;
+    vanetza::Runtime& runtime_;
+    vanetza::Clock::duration cam_interval_;
+    std::uint32_t station_id_ = 1;
+    bool print_rx_msg_ = false;
+    bool print_tx_msg_ = false;
+};
+
+#endif /* CAM_APPLICATION_HPP_EUIC2VFR */