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FLASHING.md says how to take a newer version of the colleague's tree (copy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/asn1/support/NativeInteger.h

@@ -0,0 +1,73 @@
+/*-
+ * Copyright (c) 2004-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+/*
+ * This type differs from the standard INTEGER in that it is modelled using
+ * the fixed machine type (long, int, short), so it can hold only values of
+ * limited length. There is no type (i.e., NativeInteger_t, any integer type
+ * will do).
+ * This type may be used when integer range is limited by subtype constraints.
+ */
+#ifndef	_NativeInteger_H_
+#define	_NativeInteger_H_
+
+#include "asn_application.h"
+#include "INTEGER.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern asn_TYPE_descriptor_t asn_DEF_NativeInteger;
+extern asn_TYPE_operation_t asn_OP_NativeInteger;
+
+asn_struct_free_f NativeInteger_free;
+
+#if !defined(ASN_DISABLE_PRINT_SUPPORT)
+asn_struct_print_f NativeInteger_print;
+#endif  /* !defined(ASN_DISABLE_PRINT_SUPPORT) */
+
+asn_struct_compare_f NativeInteger_compare;
+asn_struct_copy_f    NativeInteger_copy;
+
+#define NativeInteger_constraint asn_generic_no_constraint
+
+#if !defined(ASN_DISABLE_BER_SUPPORT)
+ber_type_decoder_f NativeInteger_decode_ber;
+der_type_encoder_f NativeInteger_encode_der;
+#endif  /* !defined(ASN_DISABLE_BER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_XER_SUPPORT)
+xer_type_decoder_f NativeInteger_decode_xer;
+xer_type_encoder_f NativeInteger_encode_xer;
+#endif  /* !defined(ASN_DISABLE_XER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_JER_SUPPORT)
+jer_type_decoder_f NativeInteger_decode_jer;
+jer_type_encoder_f NativeInteger_encode_jer;
+#endif  /* !defined(ASN_DISABLE_JER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_OER_SUPPORT)
+oer_type_decoder_f NativeInteger_decode_oer;
+oer_type_encoder_f NativeInteger_encode_oer;
+#endif  /* !defined(ASN_DISABLE_OER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_UPER_SUPPORT)
+per_type_decoder_f NativeInteger_decode_uper;
+per_type_encoder_f NativeInteger_encode_uper;
+#endif  /* !defined(ASN_DISABLE_UPER_SUPPORT) */
+#if !defined(ASN_DISABLE_APER_SUPPORT)
+per_type_decoder_f NativeInteger_decode_aper;
+per_type_encoder_f NativeInteger_encode_aper;
+#endif  /* !defined(ASN_DISABLE_APER_SUPPORT) */
+
+#if !defined(ASN_DISABLE_RFILL_SUPPORT)
+asn_random_fill_f NativeInteger_random_fill;
+#endif  /* !defined(ASN_DISABLE_RFILL_SUPPORT) */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _NativeInteger_H_ */