Create a ChatMessage map with role assistant.

Example usage:

iex> _message = OpenaiEx.ChatMessage.assistant("Hello, world!")
%{content: "Hello, world!", role: "assistant"}

iex> _message = OpenaiEx.ChatMessage.assistant("Hello, world!", [%{id: "call_123", function: %{name: "test", arguments: "{}"}}])
%{content: "Hello, world!", role: "assistant", tool_calls: [%{id: "call_123", function: %{name: "test", arguments: "{}"}}]}

Create a ChatMessage map with role developer.

Example usage:

iex> _message = OpenaiEx.ChatMessage.developer("Hello, world!")
%{content: "Hello, world!", role: "developer"}

Create a ChatMessage map with role system.

Example usage:

iex> _message = OpenaiEx.ChatMessage.system("Hello, world!")
%{content: "Hello, world!", role: "system"}

Create a ChatMessage map with role function.

Example usage:

iex> _message = OpenaiEx.ChatMessage.tool("call_sjflkje", "greet", "Hello, world!")
%{content: "Hello, world!", role: "tool", name: "greet", tool_call_id: "call_sjflkje"}

Create a ChatMessage map with role user.

Example usage:

iex> _message = OpenaiEx.ChatMessage.user("Hello, world!")
%{content: "Hello, world!", role: "user"}