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FLASHING.md says how to take a newer version of the colleague's tree (copy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/tools/v2x2map-0.3.0/bridge/tests/vam-vectors.json

@@ -0,0 +1,46 @@
+[
+  {
+    "fields": [
+      1,
+      0,
+      0,
+      0,
+      0,
+      0
+    ],
+    "uper": "03100000000100000009ad2748035a4e9007ffffff08eddd0f8000007e0003f50730"
+  },
+  {
+    "fields": [
+      4294967295,
+      539000000,
+      100000000,
+      65535,
+      500,
+      900
+    ],
+    "uper": "0310ffffffffffff000aae2b2e0389fd9807ffffff08eddd0f8001c27e07d3f50730"
+  },
+  {
+    "fields": [
+      42,
+      -900000000,
+      -1800000000,
+      1,
+      16383,
+      3601
+    ],
+    "uper": "03100000002a000100080000000000000007ffffff08eddd0f800708fefffff50730"
+  },
+  {
+    "fields": [
+      9,
+      900000000,
+      1800000000,
+      32768,
+      1,
+      3599
+    ],
+    "uper": "0310000000098000000b5a4e9006b49d2007ffffff08eddd0f800707fe0007f50730"
+  }
+]