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/dcc/bursty_transmit_rate_control.cpp

@@ -0,0 +1,76 @@
+#include <vanetza/common/runtime.hpp>
+#include <vanetza/dcc/bursty_transmit_rate_control.hpp>
+#include <vanetza/dcc/state_machine.hpp>
+#include <stdexcept>
+
+namespace vanetza
+{
+namespace dcc
+{
+
+BurstyTransmitRateControl::BurstyTransmitRateControl(const StateMachine& fsm, const Runtime& rt) :
+    m_burst_budget(rt), m_fsm_budget(fsm, rt), m_fsm(fsm)
+{
+}
+
+Clock::duration BurstyTransmitRateControl::delay(const Transmission& tx)
+{
+    Clock::duration delay = Clock::duration::max();
+
+    switch (tx.profile()) {
+        case Profile::DP0:
+            delay = m_burst_budget.delay();
+            break;
+        case Profile::DP1:
+        case Profile::DP2:
+        case Profile::DP3:
+            delay = m_fsm_budget.delay();
+            break;
+        default:
+            throw std::invalid_argument("Invalid DCC Profile");
+            break;
+    };
+
+    return delay;
+}
+
+Clock::duration BurstyTransmitRateControl::interval(const Transmission& tx)
+{
+    Clock::duration interval = Clock::duration::max();
+
+    switch (tx.profile()) {
+        case Profile::DP0:
+            interval = m_burst_budget.burst_period();
+            break;
+        case Profile::DP1:
+        case Profile::DP2:
+        case Profile::DP3:
+            interval = m_fsm.transmission_interval();
+            break;
+        default:
+            throw std::invalid_argument("Invalid DCC Profile");
+            break;
+    }
+
+    return interval;
+}
+
+void BurstyTransmitRateControl::notify(const Transmission& tx)
+{
+    switch (tx.profile()) {
+        case Profile::DP0:
+            m_burst_budget.notify();
+            break;
+        case Profile::DP1:
+        case Profile::DP2:
+        case Profile::DP3:
+            m_fsm_budget.notify();
+            break;
+        default:
+            throw std::invalid_argument("Invalid DCC Profile");
+            break;
+    };
+}
+
+} // namespace dcc
+} // namespace vanetza