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FLASHING.md says how to take a newer version of the colleague's tree (copy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

@@ -0,0 +1,49 @@
+# Firmware build artifacts (idf.py)
+firmware/build/
+firmware/managed_components/
+firmware/dependencies.lock
+firmware/sdkconfig.old
+firmware/sdkconfig.backup*
+
+# iOS app source is developed privately and not published in this repo
+ios/
+
+# iOS build artifacts (xcodebuild / SwiftPM)
+ios/**/build/
+ios/**/build-sim/
+ios/**/.build/
+ios/**/DerivedData/
+ios/**/xcuserdata/
+*.xcuserstate
+
+# Python venv / pycache / PyInstaller
+bridge/__pycache__/
+bridge/build/
+bridge/dist/
+bridge/*.egg-info/
+bridge/config/
+
+# Android / Gradle
+android/.gradle/
+android/build/
+android/app/build/
+android/local.properties
+android/.idea/
+android/captures/
+android/.kotlin/
+*.iml
+
+# OS / IDE
+.DS_Store
+Thumbs.db
+.vscode/
+
+# Captured frame logs
+*.itsg5
+
+# On-device USB diagnostics dumps
+blelog.txt
+*.key
+*.pem
+
+website/