replace arctic_training_files and others

[brunj7]

In the curriculum, there are many references to "artic" in folder/files naming. We should replace that.

[jeanetteclark]

Can you give more specific examples? Like what chapter this occurs in?

[brunj7]

there was the name of the repo used in one of the git session that was named artic-training-repo. I fixed that one, but I was not sure if there were others. Some figures were pointing to a sasap-repo. I think I got most of it in those sections, but have not checked yet the others. And I was thinking you might know where such references are more likely to be

[brunj7]

I just work on making them generic, not snapp specific, e.g. training-repo