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/security/verify_service.cpp

@@ -0,0 +1,66 @@
+#include <vanetza/security/verify_service.hpp>
+#include <vanetza/security/v3/certificate_cache.hpp>
+
+namespace vanetza
+{
+namespace security
+{
+
+DummyVerifyService::DummyVerifyService(VerificationReport report, CertificateValidity validity) :
+    m_report(report), m_validity(validity)
+{
+}
+
+VerifyConfirm DummyVerifyService::verify(const VerifyRequest& request)
+{
+    VerifyConfirm confirm;
+    confirm.report = m_report;
+    confirm.certificate_validity = m_validity;
+    confirm.its_aid = get_its_aid(request.secured_message);
+
+    struct MessageVisitor : boost::static_visitor<>
+    {
+        MessageVisitor(DummyVerifyService& service, VerifyConfirm& confirm) : 
+            m_service(service), m_confirm(confirm)
+        {
+        }
+
+        void operator()(const v2::SecuredMessage& msg)
+        {
+            // not implemented for v2
+        }
+
+        void operator()(const v3::SecuredMessage& msg)
+        {
+            auto signer = msg.signer_identifier();
+            m_confirm.certificate_id = v3::get_certificate_id(signer);
+
+            if (m_confirm.certificate_id) {
+                if (m_service.m_cert_cache) {
+                    if (auto cert = v3::get_certificate(signer)) {
+                        m_service.m_cert_cache->store(v3::Certificate { *cert });
+                        m_confirm.permissions = v3::get_app_permissions(*cert, m_confirm.its_aid);
+                    } else if (auto cert = m_service.m_cert_cache->lookup(*m_confirm.certificate_id)) {
+                        m_confirm.permissions = v3::get_app_permissions(*cert->content(), m_confirm.its_aid);
+                    }
+                } else if (auto cert = v3::get_certificate(signer)) {
+                    m_confirm.permissions = v3::get_app_permissions(*cert, m_confirm.its_aid);
+                }
+            }
+        }
+
+        DummyVerifyService& m_service;
+        VerifyConfirm& m_confirm;
+    } visitor(*this, confirm);
+    boost::apply_visitor(visitor, request.secured_message);
+
+    return confirm;
+}
+
+void DummyVerifyService::use_certificate_cache(v3::CertificateCache* cache)
+{
+    m_cert_cache = cache;
+}
+
+} // namespace security
+} // namespace vanetza