Add codex apply to apply a patch created from the Codex remote agent (#1528)

In order to to this, I created a new `chatgpt` crate where we can put
any code that interacts directly with ChatGPT as opposed to the OpenAI
API. I added a disclaimer to the README for it that it should primarily
be modified by OpenAI employees.


https://github.com/user-attachments/assets/bb978e33-d2c9-4d8e-af28-c8c25b1988e8

codex-rs/chatgpt/src/lib.rs

@@ -0,0 +1,4 @@
+pub mod apply_command;
+mod chatgpt_client;
+mod chatgpt_token;
+pub mod get_task;