feat(OpenaiLLMEngine.py): add orjson library for JSON serialization and deserialization, and implement the generate method to make API call to OpenAI chat completions endpoint
feat(__init__.py): import OpenaiLLMEngine in LLMEngine package
feat(BaseScriptEngine.py): add time_script method to the BaseScriptEngine class
feat(CustomScriptEngine.py): add new file CustomScriptEngine.py to handle custom script generation, implement generate method to return the provided script, and add get_options method to provide a textbox for the prompt input
feat(__init__.py): import CustomScriptEngine in ScriptEngine package
feat(__init__.py): import LLMEngine package and add OpenaiLLMEngine to the ENGINES dictionary
refactor(gradio_ui.py): change equal_height attribute of Row to False to allow different heights for input blocks
