Add Search class for handling search queries

[mekarpeles]

This pull request introduces a new Search model to standardize search parameters and refactors the DataProvider class to improve extensibility and code clarity. The most significant changes are the addition of the Search class, updates to the base provider's search method, and minor import improvements.

Search parameter handling improvements:

• Added a new Search class (subclassing BaseModel and Mapping) to encapsulate search parameters, provide dictionary-like access, and expose a params property for easy conversion to string-keyed dictionaries.

Data provider method refactoring:

• Refactored the DataProvider.search method to be a @classmethod instead of a @staticmethod, allowing subclasses to override it more easily and use cls instead of DataProvider for constructing responses. [1] [2]

Import and typing improvements:

• Added an import for Mapping from collections.abc to support the new Search class implementation.