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FLASHING.md says how to take a newer version of the colleague's tree (copy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/vanetza/common/manual_runtime.cpp

@@ -0,0 +1,89 @@
+#include "manual_runtime.hpp"
+#include <cassert>
+
+namespace vanetza
+{
+
+ManualRuntime::ManualRuntime(Clock::time_point init) : m_now(init)
+{
+}
+
+void ManualRuntime::schedule(Clock::time_point tp, const Callback& cb, const void* scope)
+{
+    m_queue.emplace(queue_type::value_type { tp, cb, scope });
+}
+
+void ManualRuntime::schedule(Clock::duration d, const Callback& cb, const void* scope)
+{
+    schedule(m_now + d, cb, scope);
+}
+
+void ManualRuntime::cancel(const void* scope)
+{
+    if (scope) {
+        auto scope_match_range = m_queue.get<by_scope>().equal_range(scope);
+        m_queue.get<by_scope>().erase(scope_match_range.first, scope_match_range.second);
+    }
+}
+
+Clock::time_point ManualRuntime::next() const
+{
+    Clock::time_point next_tp = Clock::time_point::max();
+    if (!m_queue.empty()) {
+        next_tp = m_queue.get<by_deadline>().begin()->deadline;
+    }
+    return next_tp;
+}
+
+Clock::time_point ManualRuntime::now() const
+{
+    return m_now;
+}
+
+void ManualRuntime::trigger(Clock::time_point tp)
+{
+    // require monotonic clock
+    assert(tp >= m_now);
+    m_now = tp;
+    trigger();
+}
+
+void ManualRuntime::trigger(Clock::duration d)
+{
+    m_now += d;
+    trigger();
+}
+
+void ManualRuntime::trigger()
+{
+    // process queue elements separately because callback might modify runtime
+    while (!m_queue.empty()) {
+        auto top = m_queue.get<by_deadline>().begin();
+        const auto deadline = top->deadline; // copy of deadline on purpose (erase before callback)
+        if (deadline <= m_now) {
+            Callback cb = top->callback;
+            m_queue.get<by_deadline>().erase(top);
+            // callback invocation has to be last action because it might modify runtime
+            cb(deadline);
+        } else {
+            break;
+        }
+    }
+}
+
+void ManualRuntime::reset(Clock::time_point tp)
+{
+    m_now = tp;
+    queue_type queue;
+    swap(queue, m_queue);
+
+    // invoke all callbacks once so they can re-schedule
+    for (auto& item : queue) {
+        const auto& deadline = item.deadline;
+        auto& callback = item.callback;
+        // callback might modify m_queue
+        callback(deadline);
+    }
+}
+
+} // namespace vanetza