Add create node type feature in UI

[beyse]

Is your feature request related to a problem? Please describe. Currently there is a limited number of node types. New node types must be added by creating a josn file in the right directory. This requires knowledge of the folder, the file structure and the data structure for node type definitions.

Describe the solution you'd like The user can add new node types right in the UI with a graphical node type editor. With it the user can specify the name and the type of a new node type and add inputs and outputs with their name and their data type.

Describe alternatives you've considered none

Additional context none