docs: setup docs for C code (#23262)

* add breathe and doxygen

* add sphinx-breathe c docs generation
* add c docs to site

* built in docker

* build base image first

* namespace cleanup

* Revert "build base image first"

This reverts commit 4c44c02ffb93b3f0bc3968f2ee1fdc64faa25608.

* its in the dockerfile

Co-authored-by: Willem Melching <willem.melching@gmail.com>
old-commit-hash: 9f70bea964

docs/c_docs.rst

@@ -0,0 +1,105 @@
+openpilot
+==========
+
+
+opendbc
+------
+.. autodoxygenindex::
+   :project: opendbc_can
+
+
+cereal
+------
+
+messaging
+^^^^^^^^^
+.. autodoxygenindex::
+   :project: cereal_messaging
+
+visionipc
+^^^^^^^^^
+.. autodoxygenindex::
+   :project: cereal_visionipc
+
+
+selfdrive
+---------
+
+camerad
+^^^^^^^
+.. autodoxygenindex::
+   :project: selfdrive_camerad_cameras
+.. autodoxygenindex::
+   :project: selfdrive_camerad_transforms
+.. autodoxygenindex::
+   :project: selfdrive_camerad_imgproc
+
+locationd
+^^^^^^^^^
+.. autodoxygenindex::
+   :project: selfdrive_locationd
+
+ui
+^^
+
+.. autodoxygenindex::
+   :project: selfdrive_ui
+
+soundd
+""""""
+.. autodoxygenindex::
+   :project: selfdrive_ui_soundd
+
+navd
+""""
+.. autodoxygenindex::
+   :project: selfdrive_ui_navd
+
+replay
+""""""
+.. autodoxygenindex::
+   :project: selfdrive_ui_replay
+
+qt
+""
+.. autodoxygenindex::
+   :project: selfdrive_ui_qt_offroad
+.. autodoxygenindex::
+   :project: selfdrive_ui_qt_maps
+
+proclogd
+^^^^^^^^
+.. autodoxygenindex::
+   :project: selfdrive_proclogd
+
+modeld
+^^^^^^
+.. autodoxygenindex::
+   :project: selfdrive_modeld_transforms
+.. autodoxygenindex::
+   :project: selfdrive_modeld_models
+.. autodoxygenindex::
+   :project: selfdrive_modeld_thneed
+.. autodoxygenindex::
+   :project: selfdrive_modeld_runners
+
+common
+^^^^^^
+.. autodoxygenindex::
+   :project: selfdrive_common
+
+sensorsd
+^^^^^^^^
+.. autodoxygenindex::
+   :project: selfdrive_sensord_sensors
+
+boardd
+^^^^^^
+.. autodoxygenindex::
+   :project: selfdrive_boardd
+
+
+rednose
+-------
+.. autodoxygenindex::
+   :project: rednose_repo_rednose_helpers