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/geodesy/country_database.cpp

@@ -0,0 +1,84 @@
+#include <vanetza/geodesy/country_database.hpp>
+#include <vanetza/geodesy/country_data_reader.hpp>
+#include <boost/geometry/algorithms/within.hpp>
+#include <boost/units/quantity.hpp>
+#include <fstream>
+#include <iterator>
+#include <vector>
+
+#ifdef VANETZA_WITH_EMBEDDED_COUNTRY_DATA
+#include <vanetza/common/byte_view.hpp>
+namespace vanetza { namespace geodesy { namespace country { vanetza::byte_view_range embedded(); } } }
+#endif
+
+namespace vanetza
+{
+namespace geodesy
+{
+
+CountryDatabase CountryDatabase::embedded(std::string* error)
+{
+    CountryDatabase db;
+#ifdef VANETZA_WITH_EMBEDDED_COUNTRY_DATA
+    auto view = country::embedded();
+    db.load(view.data(), view.size(), error);
+#else
+    if (error) {
+        *error = "embedded country data not available";
+    }
+#endif
+    return db;
+}
+
+bool CountryDatabase::load(const std::string& path, std::string* error)
+{
+    std::ifstream file(path, std::ios::binary);
+    if (!file) {
+        if (error) {
+            *error = "cannot open file: " + path;
+        }
+        return false;
+    }
+
+    std::vector<uint8_t> data { std::istreambuf_iterator<char>(file), std::istreambuf_iterator<char>() };
+    return load(data.data(), data.size(), error);
+}
+
+bool CountryDatabase::load(const uint8_t* data, std::size_t length, std::string* error)
+{
+    m_countries.clear();
+
+    auto result = read_country_data(data, length,
+        [this](M49Code code, CountryPolygon&& polygon) {
+            m_countries.emplace(code, std::move(polygon));
+        });
+
+    if (result.failed()) {
+        if (error) {
+            *error = result.message() + " at offset " + std::to_string(result.position());
+        }
+        m_countries.clear();
+        return false;
+    }
+
+    return true;
+}
+
+bool CountryDatabase::is_inside(M49Code country, const GeodeticPosition& position) const
+{
+    auto it = m_countries.find(country);
+    if (it == m_countries.end()) {
+        return false;
+    }
+
+    country::Point point(position.longitude / units::degree, position.latitude / units::degree);
+    return boost::geometry::within(point, it->second);
+}
+
+bool CountryDatabase::empty() const
+{
+    return m_countries.empty();
+}
+
+} // namespace geodesy
+} // namespace vanetza