Remove keys.py and replace with python-dotenv.

- Removed `keys.py`.
- Added `.env.template`.
- Added `.env` to `.gitignore`.
- Updated various files that imported `keys` to use `os.getenv` instead.
- Updated `requirements.txt` dependencies.
- Updated README.md with instructions on setting up environment variables.

This change improves security, flexibility, and makes it easier to use Auto-GPT in notebooks. Environment variables are stored in `.env` and loaded via `load_dotenv()` in `scripts/main.py`.

scripts/chat.py

@@ -1,9 +1,9 @@
+import os
 import time
 import openai
-import keys
 
 # Initialize the OpenAI API client
-openai.api_key = keys.OPENAI_API_KEY
+openai.api_key = os.getenv("OPENAI_API_KEY")
 
 
 def create_chat_message(role, content):