Add OpenAI integration (#86621)

* Add OpenAI integration

* Remove empty manifest fields

* More prompt tweaks

* Update manifest

* Update homeassistant/components/openai_conversation/config_flow.py

Co-authored-by: Franck Nijhof <git@frenck.dev>

* Address comments

* Add full integration tests

* Cripple the integration

* Test single instance

Co-authored-by: Franck Nijhof <git@frenck.dev>

homeassistant/generated/config_flows.py

@@ -297,6 +297,7 @@ FLOWS = {
         "onewire",
         "onvif",
         "open_meteo",
+        "openai_conversation",
         "openexchangerates",
         "opengarage",
         "opentherm_gw",