feat: Add model_utils and model_constants intorducing PROVIDER_NAMES and MODEL_INFO variables for dynamic updation of model data (#4341)

feat: Add model_utils and model_constants

- Enhanced the initialization logic in model_constants to handle delayed imports and circular dependencies.
- Improved type hinting for better code clarity and maintainability.

Details:
- `get_model_info`: Retrieves comprehensive information about all available models, which is used to populate the `MODEL_INFO` dictionary.
- `MODEL_INFO`: A dictionary where each key is a model identifier, and the value is a dictionary containing details about the model, such as its `display_name` and configuration options.
- `PROVIDER_NAMES`: A list derived from `MODEL_INFO` that holds the names of model providers, providing a quick reference to all available model providers.

src/backend/tests/unit/base/models/test_model_constants.py

@@ -0,0 +1,25 @@
+from src.backend.base.langflow.base.models.model_constants import ModelConstants
+
+
+def test_provider_names():
+    # Initialize the ModelConstants
+    ModelConstants.initialize()
+
+    # Expected provider names
+    expected_provider_names = [
+        "AIML",
+        "Amazon Bedrock",
+        "Anthropic",
+        "Azure OpenAI",
+        "Ollama",
+        "Vertex AI",
+        "Cohere",
+        "Google Generative AI",
+        "HuggingFace",
+        "OpenAI",
+        "Perplexity",
+        "Qianfan",
+    ]
+
+    # Assert that the provider names match the expected list
+    assert expected_provider_names == ModelConstants.PROVIDER_NAMES