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FLASHING.md says how to take a newer version of the colleague's tree (copy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

@@ -0,0 +1,109 @@
+add_vanetza_component(security
+    backend.cpp
+    backend_null.cpp
+    cam_ssp.cpp
+    decap_service.cpp
+    delegating_security_entity.cpp
+    ecc_point.cpp
+    ecdsa256.cpp
+    encap_service.cpp
+    hashed_id.cpp
+    hmac.cpp
+    key_type.cpp
+    public_key.cpp
+    persistence.cpp
+    peer_request_tracker.cpp
+    secured_message.cpp
+    sha.cpp
+    signature.cpp
+    straight_verify_service.cpp
+    verify_service.cpp
+    v2/basic_elements.cpp
+    v2/certificate.cpp
+    v2/certificate_cache.cpp
+    v2/default_certificate_validator.cpp
+    v2/ecc_point.cpp
+    v2/encryption_parameter.cpp
+    v2/header_field.cpp
+    v2/int_x.cpp
+    v2/length_coding.cpp
+    v2/naive_certificate_provider.cpp
+    v2/null_certificate_provider.cpp
+    v2/null_certificate_validator.cpp
+    v2/payload.cpp
+    v2/persistence.cpp
+    v2/public_key.cpp
+    v2/recipient_info.cpp
+    v2/region.cpp
+    v2/secured_message.cpp
+    v2/serialization.cpp
+    v2/sign_header_policy.cpp
+    v2/signature.cpp
+    v2/signer_info.cpp
+    v2/sign_service.cpp
+    v2/static_certificate_provider.cpp
+    v2/subject_attribute.cpp
+    v2/subject_info.cpp
+    v2/trailer_field.cpp
+    v2/trust_store.cpp
+    v2/validity_restriction.cpp
+    v2/verification.cpp
+    v3/asn1_conversions.cpp
+    v3/basic_elements.cpp
+    v3/boost_geometry.cpp
+    v3/certificate.cpp
+    v3/certificate_cache.cpp
+    v3/certificate_validator.cpp
+    v3/distance.cpp
+    v3/geometry.cpp
+    v3/hash.cpp
+    v3/issuer_memory_lookup.cpp
+    v3/location_checker.cpp
+    v3/secured_message.cpp
+    v3/sign_service.cpp
+    v3/naive_certificate_provider.cpp
+    v3/sign_header_policy.cpp
+    v3/static_certificate_provider.cpp
+    v3/persistence.cpp
+    v3/revocation_lookup.cpp
+    v3/trust_store.cpp
+    v3/validity_restriction.cpp
+)
+target_link_libraries(security PUBLIC Boost::headers asn1 asn1_security common net)
+target_link_libraries(security PRIVATE geodesy)
+
+if(VANETZA_WITH_PQC)
+    set_property(TARGET security APPEND PROPERTY SOURCES
+        pqc/fndsa512_oqs.cpp
+        pqc/hybrid_certificate.cpp
+        pqc/hybrid_certificate_validator.cpp)
+    target_link_libraries(security PRIVATE OQS::oqs)
+endif()
+
+if(VANETZA_WITH_CRYPTOPP)
+    set_property(TARGET security APPEND PROPERTY
+        SOURCES backend_cryptopp.cpp)
+    target_link_libraries(security PRIVATE CryptoPP::CryptoPP)
+    target_compile_definitions(security PUBLIC "VANETZA_WITH_CRYPTOPP")
+endif()
+
+if(VANETZA_WITH_OPENSSL)
+    set_property(TARGET security APPEND PROPERTY
+        SOURCES backend_openssl.cpp openssl_wrapper.cpp)
+    target_link_libraries(security PRIVATE OpenSSL::Crypto)
+    target_compile_definitions(security PUBLIC "VANETZA_WITH_OPENSSL")
+    target_compile_definitions(security PRIVATE "OPENSSL_API_COMPAT=0x10101000L")
+endif()
+
+if(NOT VANETZA_WITH_CRYPTOPP AND NOT VANETZA_WITH_OPENSSL)
+    message(WARNING "Vanetza is built without proper security backend")
+endif()
+
+# shared test data for all security tests
+set(SECURITY_TEST_ASSET_DIR "${CMAKE_CURRENT_SOURCE_DIR}/tests/assets")
+add_test_subdirectory(tests)
+add_test_subdirectory(v2/tests)
+add_test_subdirectory(v3/tests)
+if(VANETZA_WITH_PQC)
+    add_test_subdirectory(pqc/tests)
+endif()