IBX-10519: Added footer box shadow to be used in sticky footers

Author: RopRaptor

src/bundle/Resources/public/scss/_custom.scss

@@ -393,6 +393,7 @@ $ibexa-btn-hover-box-shadow: 0 calculateRem(22px) calculateRem(24px) 0 rgba($ibe
 $ibexa-btn-hover-box-shadow-dark: 0 calculateRem(22px) calculateRem(24px) 0 rgba($ibexa-color-dark, 0.2);
 $ibexa-btn-hover-box-shadow-info: 0 calculateRem(22px) calculateRem(24px) 0 rgba($ibexa-color-info, 0.5);
 $ibexa-edit-header-box-shadow: calculateRem(4px) calculateRem(22px) calculateRem(47px) 0 rgba($ibexa-color-info, 0.15);
+$ibexa-edit-footer-box-shadow: calculateRem(-2px) 0 calculateRem(20px) 0 rgba($ibexa-color-info, 0.10);
 $ibexa-edit-content-box-shadow: calculateRem(4px) calculateRem(35px) calculateRem(47px) 0 rgba($ibexa-color-info, 0.15);
 $ibexa-anchor-btn-hover-box-shadow: 0 0 calculateRem(14px) 0 rgba($ibexa-color-black, 0.05);
 $ibexa-context-menu-box-shadow: 0 calculateRem(22px) calculateRem(24px) 0 rgba($ibexa-color-info, 0.15);