Renames and naming

This is about some renames and labels in general

Document type editor, new tab and field name, see attachment. Needs to decide on label now named "Custom" and the name shown for the taxonomy field, now reading "taxonomyField"

Rename org.hippoecm.frontend.editor.plugins.field.DelegatingPropertyFieldPlugin
The differentiating feature of this plugin is not that it simply delegates to a new plugin cluster (which is what the PropertyFieldPlugin, MixinLoaderPlugin, ComparePlugin and others also do), but that it passes along to the new cluster 3 specific properties from its own configuration