Remove qgraph backend caching of sample queries

[Woozl]

When the Aragorn caching wasn't working, we did a rudimentary cache of the sample queries so they were guaranteed to return a response instantly (for demo purposes). However, these haven't been updated so they contain answers from an older version of the graph. We should remove these and rely on Aragorn/plater instead.

https://github.com/RobokopU24/qgraph/blob/14db2d934ec0eedb369d6ae289f7d1c9582cf2e1/api_routes/routes.js#L20-L27