Prettify nodes in editor

[Doralitze]

• We should only display the configuration symbol if there is actually any configuration to edit.
• Furthermore we should enforce a reasonable minimum size, such that one can actually drag them instead of clicking actions in case of a too small node.
• It would be also beneficial to display the filter type within the node, for example below the id.
• Last but not least we should visualize the required terminal data types.