user_context was missing from websocket event data, added. Also added the websocket client handle to the event data. Removed unused event data struct. Closes: IDF-1271
closes https://github.com/espressif/esp-idf/issues/3893
closes https://github.com/espressif/esp-idf/issues/3982
Closes https://github.com/espressif/esp-idf/issues/2829