[Feature Request] Refactor code to simplify the concepts

[Obs01ete]

Motivation

We need to clean up code so that the API is easier to study and use. List of required changes:

• Remove UserChatMessage and AssistantChatMessage
• Remove AssistantSystemMessage and UserSystemMessage
• Rename role from ChatMessage into role_at_backend
• Remove role from ChatMessage altogether
• Make BaseMessage, ChatMessage, SystemMessage a frozen=True dataclass
• Remove def __getattribute__ from BaseMessage (Remove __getattribute__ from BaseMessage #168)
• Replace type of content in BaseMessage with TextPrompt
• Rename model to model_type
• Fix mode_type typos (Fixed model_type typos in RolePlaying #166, Fixed model_type typos in role_playing.py examples #169)
• Extract RolePlaying into a separate societies package
• Strict signature match for BaseAgent child classes

Solution

No response

Alternatives

No response

Additional context

No response

[Obs01ete]

I think mostly the refectoring is done. The remaining open points we will address later on.

[dandansamax]

Why should we remove role from ChatMessage? I'm planning to replace ChatAgent.stored_messages with memory module. It's inconvenient for memory API design if not all message-related information stores in BaseMessage.