maintenance updates
- added function 'no_translate' that wraps the string passed with special characters to prevent translation
- reformatted function documents to be more readable
- refactored all examples to use explicit 'message_command' and 'slash_command' decorators
- renamed 'Agent.translate_config' to 'Agent.get_config'
- rename 'Agent' to 'AutoI18nAgent' with backward capability
- using pyproject.toml instead of setup.py