Feature/llm data structs (#3486)

* Organize all the llm stuff into a subpackage

* Add structs for interacting with llms

autogpt/llm/providers/openai.py

@@ -0,0 +1,37 @@
+from autogpt.llm.base import ChatModelInfo, EmbeddingModelInfo
+
+OPEN_AI_CHAT_MODELS = {
+    "gpt-3.5-turbo": ChatModelInfo(
+        name="gpt-3.5-turbo",
+        prompt_token_cost=0.002,
+        completion_token_cost=0.002,
+        max_tokens=4096,
+    ),
+    "gpt-4": ChatModelInfo(
+        name="gpt-4",
+        prompt_token_cost=0.03,
+        completion_token_cost=0.06,
+        max_tokens=8192,
+    ),
+    "gpt-4-32k": ChatModelInfo(
+        name="gpt-4-32k",
+        prompt_token_cost=0.06,
+        completion_token_cost=0.12,
+        max_tokens=32768,
+    ),
+}
+
+OPEN_AI_EMBEDDING_MODELS = {
+    "text-embedding-ada-002": EmbeddingModelInfo(
+        name="text-embedding-ada-002",
+        prompt_token_cost=0.0004,
+        completion_token_cost=0.0,
+        max_tokens=8191,
+        embedding_dimensions=1536,
+    ),
+}
+
+OPEN_AI_MODELS = {
+    **OPEN_AI_CHAT_MODELS,
+    **OPEN_AI_EMBEDDING_MODELS,
+}