Feature: Temporarily disable Sources and pivot Repository to focus on Speeches

[LuizFNJ]

Background Information

To streamline the platform and prioritize our most valuable content, we have decided to focus the "Repository" section exclusively on Speeches (Discursos). Due to low usage frequency and the need to simplify the user journey, the "Sources" (Fontes) functionality will be temporarily removed from the public interface.

How

1. Remove Sources Visibility: Temporarily hide or disable the "Sources" (Fontes) section/functionality from the main navigation and repository views.
2. Rename Repository: Update the title and references of the "Repository" (Repositório) page to "Speeches" (Discursos) or a similar term that reflects the new exclusive focus.
3. UI Cleanup: Remove any filters or UI elements related to "Sources" within the repository page to avoid user confusion.
4. Backend Preservation: Ensure the data for "Sources" remains intact in the database for future restoration, only disabling the frontend access.

Expected Behavior

The "Repository" page should now be clearly labeled and focused on Speeches, with no visible references to the "Sources" functionality, providing a more direct and prioritized experience for the user.

[thesocialdev]

Please don't change the Repository nomenclature, it's there for a reason and it's based on feedback from stakeholders (National Committee)