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/vanetza/asn1/support/aper_encoder.h

@@ -0,0 +1,63 @@
+/*-
+ * Copyright (c) 2006-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef	_APER_ENCODER_H_
+#define	_APER_ENCODER_H_
+
+#include "asn_application.h"
+#include "aper_support.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct asn_TYPE_descriptor_s;	/* Forward declaration */
+
+/*
+ * Aligned PER encoder of any ASN.1 type. May be invoked by the application.
+ * WARNING: This function returns the number of encoded bits in the .encoded
+ * field of the return value. Use the following formula to convert to bytes:
+ * 	bytes = ((.encoded + 7) / 8)
+ */
+asn_enc_rval_t aper_encode(
+    const struct asn_TYPE_descriptor_s *type_descriptor,
+    const asn_per_constraints_t *constraints,
+    const void *struct_ptr,                     /* Structure to be encoded */
+    asn_app_consume_bytes_f *consume_bytes_cb,  /* Data collector */
+    void *app_key                               /* Arbitrary callback argument */
+);
+
+/*
+ * A variant of aper_encode() which encodes data into the existing buffer
+ * WARNING: This function returns the number of encoded bits in the .encoded
+ * field of the return value.
+ */
+asn_enc_rval_t aper_encode_to_buffer(
+    const struct asn_TYPE_descriptor_s *type_descriptor,
+    const asn_per_constraints_t *constraints,
+    const void *struct_ptr,  /* Structure to be encoded */
+    void *buffer,            /* Pre-allocated buffer */
+    size_t buffer_size       /* Initial buffer size (max) */
+);
+
+/*
+ * A variant of aper_encode_to_buffer() which allocates buffer itself.
+ * Returns the number of bytes in the buffer or -1 in case of failure.
+ * WARNING: This function produces a "Production of the complete encoding",
+ * with length of at least one octet. Contrast this to precise bit-packing
+ * encoding of aper_encode() and aper_encode_to_buffer().
+ */
+ssize_t
+aper_encode_to_new_buffer(
+    const struct asn_TYPE_descriptor_s *td,
+    const asn_per_constraints_t *constraints,
+    const void *sptr,
+    void **buffer_r
+);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _APER_ENCODER_H_ */