feat: add factory for ocr engines via plugins (#1010)

* add factory for ocr engines

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* apply pre-commit after rebase

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* add picture description factory

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* fix enable option

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* switch to create methods

Signed-off-by: Panos Vagenas <pva@zurich.ibm.com>

* make `options` an explicit kwarg

Signed-off-by: Panos Vagenas <pva@zurich.ibm.com>

* keep old lock of docling-core

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* fix lock

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* add allow_external_plugins option

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

* add factory return and ignore options type

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>

---------

Signed-off-by: Michele Dolfi <dol@zurich.ibm.com>
Signed-off-by: Panos Vagenas <pva@zurich.ibm.com>
Co-authored-by: Panos Vagenas <pva@zurich.ibm.com>

docling/models/base_model.py

@@ -1,14 +1,22 @@
 from abc import ABC, abstractmethod
-from typing import Any, Generic, Iterable, Optional
+from typing import Any, Generic, Iterable, Optional, Protocol, Type
 
 from docling_core.types.doc import BoundingBox, DocItem, DoclingDocument, NodeItem
 from typing_extensions import TypeVar
 
 from docling.datamodel.base_models import ItemAndImageEnrichmentElement, Page
 from docling.datamodel.document import ConversionResult
+from docling.datamodel.pipeline_options import BaseOptions
 from docling.datamodel.settings import settings
 
 
+class BaseModelWithOptions(Protocol):
+    @classmethod
+    def get_options_type(cls) -> Type[BaseOptions]: ...
+
+    def __init__(self, *, options: BaseOptions, **kwargs): ...
+
+
 class BasePageModel(ABC):
     @abstractmethod
     def __call__(