[Aurora] Slots Manager View

[arybakov05]

The viewlet manager of Plone's Classic UI (see https://classic.demo.plone.org/en/manage-viewlets) can be ported to Seven, providing a structured overview over existing slots, as well as their subslots.

PR #8268 implements a proof of concept (which will need refinement later) of a such slots manager view. It adds the access protected @@slots view, which offers two different representations.

The first one is a flat representation of all slots as can be read from config.slots that have or had components associated with them from component registration.

The second one is more complex and renders the actual hierarchy of slots. Based on the use of the SlotRenderer inside components, a tree can recursively be created by following the rendered slots and the components registered for these slots. The result looks like this:

In a later version, some more features of the viewlet manager can be added to the slots manager view, such as unregistering ("hiding") components or rendering a preview of them.

[davisagli]

To me this seems like a feature that is more for developers than content editors. My gut feeling is that it might fit better as a CLI command rather than a component built into the CMSUI.

[arybakov05]

To me this seems like a feature that is more for developers than content editors. My gut feeling is that it might fit better as a CLI command rather than a component built into the CMSUI.

In the current state, sure, but if we copy some more features from the viewlet manager, such as hiding/showing existing slots or reordering them, then it could also appeal to site managers. I showed this to a handful of people during the sprint and all of them liked the idea

[davisagli]

I'm a bit nervous about it, because it feels like giving site admins a lot of ways to potentially break their site -- it's likely that hiding or reordering slots will render something that hasn't been considered in the site design/theme.