!!! TASK: Remove Neos.Rendering helper

[mhsdesign]

Subtask of #4478

Upgrade instructions

In case this unstable helper was used, you should look into the following alternatives or reimplement it yourself.

• labelForNodeType
  The nodes label can be fetched via node.label.

• renderDimensions
  And dimension related information can be fetched via the \Neos\Neos\Fusion\Helper\DimensionHelper (Neos.Dimension.*)

Review instructions

The helper was annotated with

These helpers are WORK IN PROGRESS and NOT STABLE YET

(okay since aaaages but still)
and we have no use for it ourselves and its not migrated yet. On a road to stable 9.0 we have to decide to either reimplement or remove.

Checklist

• Code follows the PSR-2 coding style
• Tests have been created, run and adjusted as needed
• The PR is created against the lowest maintained branch
• Reviewer - PR Title is brief but complete and starts with FEATURE|TASK|BUGFIX
• Reviewer - The first section explains the change briefly for change-logs
• Reviewer - Breaking Changes are marked with !!! and have upgrade-instructions

[ahaeslich]

@mhsdesign if someone want's to reimplement this helper for oneself couldn't we at least point to the DimensionHelper to reference how to get them?