Update routes

[JuzerShakir]

This PR focuses on updating the routes of certain actions. Here is a quick summary:

• Define a new StatisticsController controller with thaalis & sabeels actions to render its statistics respectively.
• Update the sabeels/statistics path to the statistics/sabeels path in 9c5429a.
• Redirect to sabeels_path after deleting a sabeel in dfdda46.
• Redirect to the thaalis_all_path if an authenticated user makes an unauthorized request in 9e460f5.
• Remove the thaali#index action, its routes & templates in a87a5a9.
• Set the pages#home action as a root path in 13a85e2.

Other changes include:

• Able to search thaalis in all action in 85bbdbe.
• Refactor cancancan abilities in 26e5188.