Support new Drupal 8.3 layout_discovery core module and decommission layout_plugin

[mattlt]

The layout_discovery module has been introduced into core as an experimental module. Panels and Panelizer have created new branches that drop support of layout_plugin in favor of layout_discovery.

Specifically the ui_patterns_layouts module.

Might be a good idea to open a new branch that does the same to help with testing?

Thanks,

•• matt

[ademarco]

Yep, we definitely need to address that, thanks for reminding! I'll try to take care of it asap.

[hctom]

+1 for this because currently a site will horribly break if using Display Suite and being updated to Drupal 8.3 ;)

[ademarco]

Work just started here. :)

[ademarco]

It seems all good, we now need to use a proper deriver instead of an hook alter and to provide an update hook. I'd also set 8.3 core constraint in main composer.json.

[ademarco]

Ok done, latest dev now supports Drupal >=8.3.