Add the old Skyboxes

I personally don't like the realistic skyboxes cos they clash with the cartoony art style of the game.
I thought the previous Skyboxes looked better cos they fit the game more than the Realistic ones.
The Realistic ones look a bit lazy as it looks like a bought asset from Unity Asset Store or from other 3rd party site.

Review the project history and available assets to identify which skyboxes the issue refers to as the old ones. Compare them with the current realistic skyboxes in the game and confirm the selected replacement fits the cartoony art style. Done means the previous-looking skyboxes are restored and visible in the relevant game scenes.

Written by the indexing model from the issue text.