Allow search to specify optional metadata.title

[mekarpeles]

This pull request enhances the search functionality in the OPDS2 provider by allowing a custom title to be passed through the search process and included in the search response. This improves the flexibility of catalog generation and enables more descriptive search result pages.

Enhancements to search functionality:

• Added an optional title parameter to the search method in DataProvider, allowing callers to specify a custom title for search results. [1] [2]
• Updated the SearchResponse class to include a title attribute, ensuring the title is available in the search response.
• Modified the call to Catalog.create within the search method to pass the new title parameter.

Catalog creation improvements:

• Updated the Catalog.create method to use the provided response.title as the default catalog title if no metadata is supplied, resulting in more meaningful catalog titles for search results.