Improve Project Browser compatibility and project page

Problem/Motivation
The Poll Private module does not currently display a logo in the Project Browser and may not have an assigned subject category. Additionally, the project page on Drupal.org lacks a proper description, which limits the module’s visibility and clarity for potential users.

Proposed Resolution
Add a logo to the repository, assign a relevant subject for Project Browser compatibility, and provide a clear and concise description on the module’s project page.

Tasks to Complete:

• Add a logo.png file to the root of the Poll Private module repository.
• In the module’s .info.yml file, define the appropriate subject(s).
• Add or update the project description on the Drupal.org module page to explain the module’s functionality and use case.
• Confirm that the logo and subject appear correctly in the Project Browser.