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FLASHING.md says how to take a newer version of the colleague's tree (copy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

@@ -0,0 +1,69 @@
+/*
+ * Generated by asn1c
+ * From ASN.1 module "EfcDsrcApplication"
+ * 	found in "ISO14906-0-6.asn"
+ * 	`asn1c -fcompound-names -fincludes-quoted -no-gen-example -R`
+ */
+
+#ifndef	_ChannelId_H_
+#define	_ChannelId_H_
+
+
+#include "asn_application.h"
+
+/* Including external dependencies */
+#include "NativeInteger.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Dependencies */
+typedef enum ChannelId {
+	ChannelId_obu	= 0,
+	ChannelId_sam1	= 1,
+	ChannelId_sam2	= 2,
+	ChannelId_icc	= 3,
+	ChannelId_display	= 4,
+	ChannelId_buzzer	= 5,
+	ChannelId_printer	= 6,
+	ChannelId_serialInterface	= 7,
+	ChannelId_parallelInterface	= 8,
+	ChannelId_gPS	= 9,
+	ChannelId_tachograph	= 10,
+	ChannelId_privateUse1	= 11,
+	ChannelId_privateUse2	= 12,
+	ChannelId_privateUse3	= 13,
+	ChannelId_privateUse4	= 14,
+	ChannelId_privateUse5	= 15,
+	ChannelId_bluetooth	= 16
+} e_ChannelId;
+
+/* ChannelId */
+typedef long	 ChannelId_t;
+
+/* Implementation */
+extern asn_oer_constraints_t asn_OER_type_ChannelId_constr_1;
+extern asn_per_constraints_t asn_PER_type_ChannelId_constr_1;
+extern asn_TYPE_descriptor_t asn_DEF_ChannelId;
+asn_struct_free_f ChannelId_free;
+asn_struct_print_f ChannelId_print;
+asn_constr_check_f ChannelId_constraint;
+ber_type_decoder_f ChannelId_decode_ber;
+der_type_encoder_f ChannelId_encode_der;
+xer_type_decoder_f ChannelId_decode_xer;
+xer_type_encoder_f ChannelId_encode_xer;
+jer_type_encoder_f ChannelId_encode_jer;
+oer_type_decoder_f ChannelId_decode_oer;
+oer_type_encoder_f ChannelId_encode_oer;
+per_type_decoder_f ChannelId_decode_uper;
+per_type_encoder_f ChannelId_encode_uper;
+per_type_decoder_f ChannelId_decode_aper;
+per_type_encoder_f ChannelId_encode_aper;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif	/* _ChannelId_H_ */
+#include "asn_internal.h"