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FLASHING.md says how to take a newer version of the colleague's tree (copy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