Python: Proper separation of unit and integration tests (#732)

### Motivation and Context
This PR introduces the ability to run formal integration tests for
python using pytest - separated from unit tests for easier automation.

### Description
- moved `python/tests/end-to-end` directory to
`python/tests/integration`
- renamed integration tests to test_* pattern so pytest will detect them
- import `GenerationConfig` for hugging face completions - according to
logs, this is the recommended practice

python/semantic_kernel/connectors/ai/hugging_face/services/hf_text_completion.py

@@ -4,7 +4,7 @@ from logging import Logger
 from typing import Optional
 
 import torch
-from transformers import pipeline
+from transformers import GenerationConfig, pipeline
 
 from semantic_kernel.connectors.ai.ai_exception import AIException
 from semantic_kernel.connectors.ai.complete_request_settings import (
@@ -69,14 +69,15 @@ class HuggingFaceTextCompletion(TextCompletionClientBase):
             str -- Completion result.
         """
         try:
-            result = self.generator(
-                prompt,
-                num_return_sequences=1,
+            generation_config = GenerationConfig(
                 temperature=request_settings.temperature,
                 top_p=request_settings.top_p,
-                max_length=request_settings.max_tokens,
+                max_new_tokens=request_settings.max_tokens,
                 pad_token_id=50256,  # EOS token
             )
+            result = self.generator(
+                prompt, num_return_sequences=1, generation_config=generation_config
+            )
 
             if self._task == "text-generation" or self._task == "text2text-generation":
                 return result[0]["generated_text"]

python/semantic_kernel/connectors/ai/open_ai/services/open_ai_text_embedding.py

@@ -48,6 +48,9 @@ class OpenAITextEmbedding(EmbeddingGeneratorBase):
         import openai
 
         openai.api_key = self._api_key
+        openai.api_base = "https://api.openai.com/v1"
+        openai.api_type = "openai"
+        openai.api_version = None
         if self._org_id is not None:
             openai.organization = self._org_id