submenu items list

This file stores all items of "Add Node" menu.
Every entry is organized as follows:
(node.rna_type.identifier, node.type, node.rna_type.name)

example:
('ShaderNodeTexCoord', 'TEX_COORD', 'Texture Coordinate'),

Can be used as "items" of enum property of operator that adds nodes in
exactly the same manner as regular "Add Node", or for swapping node
types.

Goal is to use this in new "Swap Type" class