Add blocks grouping feature

[revnelson]

It'd be great to be able to group Blocks so we can, for example, have a UI blocks group and a Containers blocks group. Currently we've got UI blocks such as Buttons, Heros, WYSIWYGs (richText), etc. and then Container blocks such as Grid, Flex, Carousel, etc. It would make our editor's lives much easier to see groups so they can pick the appropriate block at a glance. A group field could be added to the admin config for blocks similar to collections.

[Sandro48]

+1 for this, if you have a lot of layout blocks, it just looks messy