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/parser.hpp

@@ -0,0 +1,45 @@
+#ifndef PARSER_HPP_IBDRMPKB
+#define PARSER_HPP_IBDRMPKB
+
+#include <vanetza/common/byte_buffer.hpp>
+#include <vanetza/common/byte_buffer_source.hpp>
+#include <vanetza/geonet/header_type.hpp>
+#include <vanetza/geonet/header_variant.hpp>
+#include <vanetza/security/secured_message.hpp>
+#include <boost/iostreams/stream.hpp>
+#include <boost/range/iterator_range.hpp>
+#include <cstdint>
+
+namespace vanetza
+{
+namespace geonet
+{
+
+// forward declarations
+struct BasicHeader;
+struct CommonHeader;
+
+class Parser
+{
+public:
+    Parser(ByteBuffer::const_iterator begin, ByteBuffer::const_iterator end);
+    Parser(boost::iterator_range<ByteBuffer::const_iterator> range);
+
+    std::size_t parse_basic(BasicHeader&);
+    std::size_t parse_common(CommonHeader&);
+    std::size_t parse_secured(security::SecuredMessage&);
+    std::size_t parse_extended(HeaderVariant&, HeaderType);
+    std::size_t parsed_bytes() const;
+
+private:
+    byte_buffer_source m_byte_buffer_source;
+    boost::iostreams::stream_buffer<byte_buffer_source> m_stream;
+    InputArchive m_archive;
+    std::size_t m_read_bytes;
+};
+
+} // namespace geonet
+} // namespace vanetza
+
+#endif /* PARSER_HPP_IBDRMPKB */
+