Use `fetch()` global function for http-requests over `axios`-library

[kahlstrm]

Given that fetch is available on all modern browsers and has been for quite many years, I wonder if there are any blockers in adapting the material to use that over the axios-library?
Is there a pedagogical reasons for using axios over the standard fetch, or is this just a remnant of the past when fetch wasn't widely available?

I'd argue that fetch is currently the de facto method for making HTTP-requests on the browser (and node), and would be a more practical API to learn over axios.

If this is something that is deemed a good idea, at some point in time I could contribute with PRs changing the Finnish and English materials and starter templates to use fetch. But anyone else is also free to contribute and pick this up.

[mluukkai]

This is a good point. I'll consider this change for the 2025 edition!