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/asn1/release2/TS103097v211-Extension.asn

@@ -0,0 +1,52 @@
+EtsiTs103097ExtensionModule
+{itu-t(0) identified-organization(4) etsi(0) itsDomain(5) wg5(5) secHeaders(103097) extension(2) major-version-1(1) minor-version-1(1)} 
+DEFINITIONS AUTOMATIC TAGS ::= BEGIN
+
+IMPORTS 
+  HashedId8,
+  Time32
+FROM Ieee1609Dot2BaseTypes {iso(1) identified-organization(3) ieee(111) 
+    standards-association-numbered-series-standards(2) wave-stds(1609)  
+    dot2(2) base(1) base-types(2) major-version-2 (2) minor-version-3 (3)}
+WITH SUCCESSORS    
+;
+
+ExtensionModuleVersion::= INTEGER(1)
+
+Extension {EXT-TYPE : ExtensionTypes} ::= SEQUENCE {
+    id      EXT-TYPE.&extId({ExtensionTypes}),
+    content EXT-TYPE.&ExtContent({ExtensionTypes}{@.id})
+}
+
+EXT-TYPE ::= CLASS {
+    &extId        ExtId,
+    &ExtContent
+} WITH SYNTAX {&ExtContent IDENTIFIED BY &extId} 
+
+ExtId ::= INTEGER(0..255)
+
+EtsiOriginatingHeaderInfoExtension ::= Extension{{EtsiTs103097HeaderInfoExtensions}}
+
+EtsiTs103097HeaderInfoExtensionId ::= ExtId
+   etsiTs102941CrlRequestId      EtsiTs103097HeaderInfoExtensionId ::= 1 --'01'H
+   etsiTs102941DeltaCtlRequestId EtsiTs103097HeaderInfoExtensionId ::= 2 --'02'H
+
+EtsiTs103097HeaderInfoExtensions EXT-TYPE ::= {
+   { EtsiTs102941CrlRequest       IDENTIFIED BY etsiTs102941CrlRequestId } |
+   { EtsiTs102941DeltaCtlRequest  IDENTIFIED BY etsiTs102941DeltaCtlRequestId },
+   ...
+}
+
+EtsiTs102941CrlRequest::= SEQUENCE {
+    issuerId        HashedId8,
+    lastKnownUpdate Time32 OPTIONAL
+}
+
+EtsiTs102941CtlRequest::= SEQUENCE {
+    issuerId             HashedId8,
+    lastKnownCtlSequence INTEGER (0..255) OPTIONAL
+}
+
+EtsiTs102941DeltaCtlRequest::= EtsiTs102941CtlRequest
+
+END