Add layout block supports / allow align wide/full-width inside

[gaambo]

Originally reported here: https://wordpress.org/support/topic/cover-block-width-not-working-properly/#post-18102828

At the moment the slide block does not have the align/alignWide block support, because (I think) it clashes with swiper styles and width calculation. That also means that you cannot put a block (e.g.) a cover block inside a slide and have it set to full-width.

The layout block support might be needed probably on the slide block (not on the slider block).