Store chat history with stream update

[ushinnary]

Rework of chat history feature, including :

• New route for stream chat with history included (thanks to @ZBcheng for example)
• New possibility to clear history
• • clear_messages_for_id
• • clear_all_messages
• ChatId may now accept String and &str
• Added test for chat stream with history
• If message has no content or images, it will not be stored
• • Updated tests for this part
• Removed async history