Improve the efficiency of node group template creation

When creating a node group template, there is a long pause between selecting your plugin and the node group template creation form coming up. This is due to an expensive call that fetches all of the configuration entries that are possible for the chosen plugin (upward of 250k of json that has to be processed and turned into fields (which are mostly hidden and will never be unhidden)).
The aim of this blueprint is to reduce that "pause" by making the initial call only fetch the configs that are considered "top level", ie: the ones that are displayed by default in a given tab. If someone does click on the "Show full configuration" button, that will trigger an ajax callback to get the full config list to be processed and displayed.