Build concise agent system prompt

[halirutan]

The agent will always be called with the following structure:

[
  ("system", "THIS IS THE SYSTEM PROMPT WE NEED"),
  ("assistant", "Hello, how can I help you"),
  ("user", "Question 1"),
  ("assistant", "Answer 1"),
  ("user", "Question 2"),
   ...     
]

Right now, we only use the basic_intro prompt for the system prompt.

• Clean up existing agent prompts after verifying that we collected important info for tool prompts
• Take a look at the system prompt again (maybe compare with existing system prompts in langchain hub?)