Langchain integration (#512)

* Added LangChain integration

* Fixed issue created by git checkin process

* Added ':' to characters to remove from end of file path

* Tested initial migration to LangChain, removed comments and logging used for debugging

* Tested initial migration to LangChain, removed comments and logging used for debugging

* Converted camelCase to snake_case

* Turns out we need the exception handling

* Testing Hugging Face Integrations via LangChain

* Added LangChain loadable models

* Renames "qa" prompt to "clarify", since it's used in the "clarify" step, asking for clarification

* Fixed loading model yaml files

* Fixed streaming

* Added modeldir cli option

* Fixed typing

* Fixed interaction with token logging

* Fix spelling + dependency issues + typing

* Fix spelling + tests

* Removed unneeded logging which caused test to fail

* Cleaned up code

* Incorporated feedback

- deleted unnecessary functions & logger.info
- used LangChain ChatLLM instead of LLM to naturally communicate with gpt-4
- deleted loading model from yaml file, as LC doesn't offer this for ChatModels

* Update gpt_engineer/steps.py

Co-authored-by: Anton Osika <anton.osika@gmail.com>

* Incorporated feedback

- Fixed failing test
- Removed parsing complexity by using # type: ignore
- Replace every ocurence of ai.last_message_content with its content

* Fixed test

* Update gpt_engineer/steps.py

---------

Co-authored-by: H <holden.robbins@gmail.com>
Co-authored-by: Anton Osika <anton.osika@gmail.com>

gpt_engineer/chat_to_files.py

@@ -9,7 +9,7 @@ def parse_chat(chat):  # -> List[Tuple[str, str]]:
     files = []
     for match in matches:
         # Strip the filename of any non-allowed characters and convert / to \
-        path = re.sub(r'[<>"|?*]', "", match.group(1))
+        path = re.sub(r'[\:<>"|?*]', "", match.group(1))
 
         # Remove leading and trailing brackets
         path = re.sub(r"^\[(.*)\]$", r"\1", path)
@@ -18,7 +18,7 @@ def parse_chat(chat):  # -> List[Tuple[str, str]]:
         path = re.sub(r"^`(.*)`$", r"\1", path)
 
         # Remove trailing ]
-        path = re.sub(r"\]$", "", path)
+        path = re.sub(r"[\]\:]$", "", path)
 
         # Get the code
         code = match.group(2)