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/TS103301v211-IVIM.asn

@@ -0,0 +1,40 @@
+-- @brief Specification of the In vehicle information Message ETSI TS 103 301
+-- Latest version available at @url https://forge.etsi.org/rep/ITS/asn1/is_ts103301.git
+
+IVIM-PDU-Descriptions {
+    itu-t (0) identified-organization (4) etsi (0) itsDomain (5) wg1 (1) ts103301 (103301) ivim (2) version2 (2)
+}
+
+DEFINITIONS AUTOMATIC TAGS ::=
+
+BEGIN
+
+IMPORTS
+
+-- @brief Include ISO 19321
+-- Include references from @url https://standards.iso.org/iso/ts/19321/ed-2/en/ISO19321IVIv2.asn
+IviStructure
+FROM IVI { iso (1) standard (0) ivi (19321) version2 (2) }
+
+-- @brief Include ETSI TS 102 894-2
+-- Include references from @url https://forge.etsi.org/rep/ITS/ITS_ASN1/blob/master/CDD_TS102894-2/ITS-Container.asn
+ItsPduHeader
+FROM ITS-Container { itu-t (0) identified-organization (4) etsi (0) itsDomain (5) wg1 (1) ts (102894) cdd (2) version (2)};
+
+-- In vehicle information Message Message
+
+-- @brief In vehicle information Message Root
+-- This DF includes DEs for the IVIM protocolVersion, the IVI message type identifier _messageID_,
+-- the station identifier _stationID_ of the originating ITS-S and the IVI data from ISO TS 19321.
+IVIM ::= SEQUENCE {
+    -- @details header
+    -- The DE _protocolVersion_ is used to select the appropriate protocol decoder at the receiving ITS-S.
+    --   It shall be set to 2.
+    -- The DE _messageID_ shall be ivim(6).
+    header  ItsPduHeader,
+    -- @details ivi
+    -- The DE _ivi_ contains the IVI data as defined in ISO TS 19321.
+    ivi     IviStructure
+}
+
+END