docs: Add readthedocs configuration

docs/.readthedocs.yaml

@@ -0,0 +1,19 @@
+# SPDX-FileCopyrightText: Copyright DB InfraGO AG and contributors
+# SPDX-License-Identifier: CC0-1.0
+
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+version: 2
+
+build:
+  os: ubuntu-22.04
+  tools:
+    python: '3.11'
+
+mkdocs:
+  configuration: docs/mkdocs.yml
+
+python:
+  install:
+    - requirements: docs/requirements.txt