Lite chaining updates

[thekaranacharya]

• Add keyword argument on to both Guard().use() and Guard().use_many() to specify where the validation will take place. Valid options for on are : prompt, instructions, msg_history and output. This is as per new design choices for a better developer experience.
• Refactor use() and use_many() accordingly to make these changes
• Add both unit and integration tests that significantly and especially prompt and output validation.
• The following methods are now deprecated:
  • with_prompt_validation
  • with_msg_history_validation
  • with_instructions_validation