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FLASHING.md says how to take a newer version of the colleague's tree (copy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/security/r2/AcpcSsp.c

@@ -0,0 +1,81 @@
+/*
+ * Generated by asn1c
+ * From ASN.1 module "Ieee1609Dot2Dot1Protocol"
+ * 	found in "Ieee1609Dot2Dot1Protocol.asn"
+ * 	`asn1c -fcompound-names -fincludes-quoted -no-gen-example -fprefix=Vanetza_Security2_ -R`
+ */
+
+#include "AcpcSsp.h"
+
+#if !defined(ASN_DISABLE_OER_SUPPORT)
+static asn_oer_constraints_t asn_OER_type_Vanetza_Security2_AcpcSsp_constr_1 CC_NOTUSED = {
+	{ 0, 0 },
+	-1};
+#endif  /* !defined(ASN_DISABLE_OER_SUPPORT) */
+#if !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT)
+static asn_per_constraints_t asn_PER_type_Vanetza_Security2_AcpcSsp_constr_1 CC_NOTUSED = {
+	{ APC_CONSTRAINED | APC_EXTENSIBLE,  0,  0,  0,  0 }	/* (0..0,...) */,
+	{ APC_UNCONSTRAINED,	-1, -1,  0,  0 },
+	0, 0	/* No PER value map */
+};
+#endif  /* !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT) */
+static asn_TYPE_member_t asn_MBR_Vanetza_Security2_AcpcSsp_1[] = {
+	{ ATF_NOFLAGS, 0, offsetof(struct Vanetza_Security2_AcpcSsp, choice.cam),
+		(ASN_TAG_CLASS_CONTEXT | (0 << 2)),
+		-1,	/* IMPLICIT tag at current level */
+		&asn_DEF_Vanetza_Security2_CamSsp,
+		0,
+		{
+#if !defined(ASN_DISABLE_OER_SUPPORT)
+			0,
+#endif  /* !defined(ASN_DISABLE_OER_SUPPORT) */
+#if !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT)
+			0,
+#endif  /* !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT) */
+#if !defined(ASN_DISABLE_JER_SUPPORT)
+			0,
+#endif  /* !defined(ASN_DISABLE_JER_SUPPORT) */
+			0
+		},
+		0, 0, /* No default value */
+		"cam"
+		},
+};
+static const asn_TYPE_tag2member_t asn_MAP_Vanetza_Security2_AcpcSsp_tag2el_1[] = {
+    { (ASN_TAG_CLASS_CONTEXT | (0 << 2)), 0, 0, 0 } /* cam */
+};
+static asn_CHOICE_specifics_t asn_SPC_Vanetza_Security2_AcpcSsp_specs_1 = {
+	sizeof(struct Vanetza_Security2_AcpcSsp),
+	offsetof(struct Vanetza_Security2_AcpcSsp, _asn_ctx),
+	offsetof(struct Vanetza_Security2_AcpcSsp, present),
+	sizeof(((struct Vanetza_Security2_AcpcSsp *)0)->present),
+	asn_MAP_Vanetza_Security2_AcpcSsp_tag2el_1,
+	1,	/* Count of tags in the map */
+	0, 0,
+	1	/* Extensions start */
+};
+asn_TYPE_descriptor_t asn_DEF_Vanetza_Security2_AcpcSsp = {
+	"AcpcSsp",
+	"AcpcSsp",
+	&asn_OP_CHOICE,
+	0,	/* No effective tags (pointer) */
+	0,	/* No effective tags (count) */
+	0,	/* No tags (pointer) */
+	0,	/* No tags (count) */
+	{
+#if !defined(ASN_DISABLE_OER_SUPPORT)
+		&asn_OER_type_Vanetza_Security2_AcpcSsp_constr_1,
+#endif  /* !defined(ASN_DISABLE_OER_SUPPORT) */
+#if !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT)
+		&asn_PER_type_Vanetza_Security2_AcpcSsp_constr_1,
+#endif  /* !defined(ASN_DISABLE_UPER_SUPPORT) || !defined(ASN_DISABLE_APER_SUPPORT) */
+#if !defined(ASN_DISABLE_JER_SUPPORT)
+		0,
+#endif  /* !defined(ASN_DISABLE_JER_SUPPORT) */
+		CHOICE_constraint
+	},
+	asn_MBR_Vanetza_Security2_AcpcSsp_1,
+	1,	/* Elements count */
+	&asn_SPC_Vanetza_Security2_AcpcSsp_specs_1	/* Additional specs */
+};
+