Replace Page List Block with Custom Nav Items and Refactor Spacing in Footer

[amjadr360]

This PR will close https://github.com/extendify/company-product/issues/570

In this PR:

• The page list block in the footers is replaced with custom nav items
• Spacing is refactored in the footers, using step spacing instead of custom spacing

• Remove the unwanted Margin top from Template Part Block