Add Customization Parameters

[PierreEtienneJ]

Currently, the project provides automated API documentation similar to Sphinx's auto-api.
However, there is limited flexibility in customizing the generated output.

Describe the solution you'd like

To improve customization, I propose introducing two new parameters:

• rust_root_pages (str, default: "api/crates") Allows users to change the root path for generated pages.
• rust_enable_auto_pages (bool, default: True) If set to False, prevents automatic page generation.

These parameters will provide users with greater control over how documentation is structured and generated.

[PierreEtienneJ]

And maybe can add parameter rust_keep_files (bool) like autoapi_keep_files from autoapi sphinx extension for python.