WIP: Feature: switch to "special edit mode" for single content element

[mhsdesign]

Description

This marks ofcouse already a solution to an issue, so its a thread about the implementation.
The issue would be: How to make complex content fast editable / suited for the neos backend.
Our thesis is, that one should have to switch to the rawContentMode, just to edit one more complex element.

integrate the idea of https://github.com/CarbonPackages/Carbon.CBD thanks to @jonnitto into the Neos Ui

sorry for the name "special mode" but it is special ;) And WIP.

Problems & Solutions:

rawContentMode as fallback for CEs if no custom special rendering defined neos/neos-development-collection#3767
-> needs to be not affected by the general css on the page -> use shadow dom -> but what if a content collection is rendered in rawContentMode and the children in special custom mode (depending on global css?) -> is this possible to switch back to global css context from within a shadow dom maybe slots?
-> or do we not need shadow dom and hope that styles dont interfere to much?

-> when out of band rendering contents, they need to signal somehow that they are in special mode?
can we hijack the ContentCase with a condition that checks for node.context.editMode == "specialMode" or similar? Note that changing the edit mode is done in the session and not supposed to be on per node basis: see also link

-> children of an upper element that was changed to special content mode should also be rendered in special mode even when reloadIfChanged

-> the option if an element should be editable in special mode should be adjustable by the integrator in the nodeType

[jonnitto]

If the node has the needed props or children, show live view per default. (and show edit button)

After the user clicked on the edit button, show editable content (In this case a content collection)
Also show the live button. In Carbon.CBD, the window get reloaded on click

If not all requirements are met, show an message: