feat: implement rdfproxy.ConfigDict extension for model configs

Currently, the rdfproxy custom settings for pydantic.ConfigDict are rightfully flagged by static checkers.
Subclassing pydantic.ConfigDict and providing rdfproxy-specific config
options solves this problem and provides better IDE support for
instantiating model configs.

Closes #159.

rdfproxy/__init__.py

@@ -1,4 +1,4 @@
 from rdfproxy.adapter import SPARQLModelAdapter  # noqa: F401
 from rdfproxy.mapper import ModelBindingsMapper  # noqa: F401
-from rdfproxy.utils._types import SPARQLBinding  # noqa: F401
+from rdfproxy.utils._types import ConfigDict, SPARQLBinding  # noqa: F401
 from rdfproxy.utils.models import Page, QueryParameters  # noqa: F401

rdfproxy/utils/_types.py

@@ -3,7 +3,7 @@
 from collections.abc import Iterable
 from typing import Protocol, TypeAlias, TypeVar, runtime_checkable
 
-from pydantic import BaseModel
+from pydantic import BaseModel, ConfigDict as PydanticConfigDict
 
 
 _TModelInstance = TypeVar("_TModelInstance", bound=BaseModel)
@@ -42,3 +42,10 @@ def __call__(self, model: BaseModel) -> bool: ...
 
 
 _TModelBoolValue: TypeAlias = ModelBoolPredicate | str | Iterable[str]
+
+
+class ConfigDict(PydanticConfigDict, total=False):
+    """pydantic.ConfigDict extension for RDFProxy model_config options."""
+
+    group_by: str
+    model_bool: _TModelBoolValue