Feat: Performance Tests

[jeswr]

In light of the current work being done, it may be worth looking into getting some CI workflows running that do performance tests on this code in a consistent environment (perhaps something like https://stackify.com/node-js-performance-tuning/) so that there are no performance regressions in the future.

At the same time it possibly be worth setting up similar workflows in Comunica, @rubensworks do you think something like this may be appropriate for a bounty - especially since it is a task that someone can do without having too deep of a knowledge of the codebases.

[rubensworks]

@jeswr Great idea! Could you have a first go at writing out a bounty issue over at the Comunica repo? Depending on what you have in mind exactly, it might make sense to partially build upon https://github.com/comunica/rdf-test-suite-ldf.js