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FLASHING.md says how to take a newer version of the colleague's tree (copy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/tools/benchmark/cases/security/base.hpp

@@ -0,0 +1,37 @@
+#ifndef BENCHMARK_CASES_SECURITY_BASE_HPP
+#define BENCHMARK_CASES_SECURITY_BASE_HPP
+
+#include "case.hpp"
+#include <vanetza/common/manual_runtime.hpp>
+#include <vanetza/common/stored_position_provider.hpp>
+#include <vanetza/security/backend.hpp>
+#include <vanetza/security/delegating_security_entity.hpp>
+#include <vanetza/security/v2/certificate_cache.hpp>
+#include <vanetza/security/v2/default_certificate_validator.hpp>
+#include <vanetza/security/v2/naive_certificate_provider.hpp>
+#include <vanetza/security/v2/sign_header_policy.hpp>
+#include <vanetza/security/v2/trust_store.hpp>
+
+class SecurityBaseCase : public Case
+{
+public:
+    SecurityBaseCase();
+
+    void prepare() override;
+
+protected:
+    vanetza::ManualRuntime runtime;
+    vanetza::StoredPositionProvider positioning;
+    std::unique_ptr<vanetza::security::Backend> crypto_backend;
+    vanetza::security::v2::TrustStore trust_store;
+    vanetza::security::v2::CertificateCache certificate_cache;
+    vanetza::security::v2::NaiveCertificateProvider certificate_provider;
+    vanetza::security::v2::DefaultCertificateValidator certificate_validator;
+    vanetza::security::v2::DefaultSignHeaderPolicy sign_header_policy;
+    vanetza::security::DelegatingSecurityEntity security_entity;
+
+    std::unique_ptr<vanetza::security::SignService> create_sign_service();
+    std::unique_ptr<vanetza::security::VerifyService> create_verify_service();
+};
+
+#endif /* BENCHMARK_CASES_SECURITY_BASE_HPP */