Use a configuration template base class for hierarchies that use Super<>

[dimitar-asenov]

For example, for make all visualizations inherit from a configuration template, which in turn directly inherits from Super<Item>. The template is a thin wrapper on top that just exports the new visualization's style, node, and top-level class as types. This will make a lot of things simpler when declaring objects.

A problem might be inheriting visualizations (e.g. in TextRenderer) where multiple configurations are needed throughout the hierarchy. This needs to be investigated.