Gen Schema should pull the list of attributes at runtime

[willwill96]

The function that generates the MetacardAttributes graphql list is based on a static list of attributes https://github.com/connexta/revelio/blob/master/src/main/webapp/intrigue-api/metacards/gen-schema.js

This means that file needs to be updated any time a new attribute is added to ddf and also means that downstream projects with their own custom attributes need to maintain their own static list of their attributes.

We should base this off of the system instead, pulling them at runtime if possible.