Look into and test conditional request implementation

[biskit1]

As mentioned in pull request #34, we should see if we can use conditional requests to limit the amount of requests being made when the program is run.

@0xazure is it alright if I take this up?

[0xazure]

I've been thinking about this a bit more, and as you mention in #34:

Not sure how it would work between each program run

you're definitely on the right track here, we need to somehow cache the results of the ETag and Last-Modified headers for this to be viable between runs.

I had a feeling we would need to do some level of caching of results using a JSON API request approach, and caching is notoriously finnicky to implement correctly. I think we should explore options like #31 first before investing the time in caching conditional request headers.