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/geonet/position_updater.cpp

@@ -0,0 +1,53 @@
+#include <vanetza/common/position_provider.hpp>
+#include <vanetza/common/runtime.hpp>
+#include <vanetza/geonet/position_updater.hpp>
+#include <vanetza/geonet/router.hpp>
+#include <vanetza/units/time.hpp>
+#include <chrono>
+
+namespace vanetza
+{
+namespace geonet
+{
+
+PositionUpdater::PositionUpdater(Runtime& rt, PositionProvider& position, Router& router) :
+    m_runtime(rt), m_positioning(position), m_router(router)
+{
+    update_rate(m_router.get_mib().itsGnMinimumUpdateFrequencyEPV);
+}
+
+PositionUpdater::~PositionUpdater()
+{
+    m_runtime.cancel(this);
+}
+
+void PositionUpdater::schedule()
+{
+    if (m_interval > Clock::duration::zero()) {
+        m_runtime.schedule(m_interval, [this](Clock::time_point) {
+                m_router.update_position(m_positioning.position_fix());
+                schedule();
+        }, this);
+    }
+}
+
+void PositionUpdater::update_rate(Clock::duration interval)
+{
+    m_interval = interval;
+    m_runtime.cancel(this); /*< cancel previously scheduled callback */
+    schedule();
+}
+
+void PositionUpdater::update_rate(units::Frequency rate)
+{
+    if (rate > units::Frequency::from_value(0.0)) {
+        using namespace std::chrono;
+        const duration<double> interval { 1.0 / rate / units::si::second };
+        update_rate(duration_cast<Clock::duration>(interval));
+    } else {
+        update_rate(Clock::duration::zero());
+    }
+}
+
+} // namespace geonet
+} // namespace vanetza