make utils package a subpackage

[heather999]

As discussed on desc-help, we are going to make utils a subpackage and update the pypi installation appropriately.

[heather999]

Dear @Catarina-Alves I'm sorry for the long delay - I have started to look at this again and will try to get back to you early next week!

[Catarina-Alves]

Hi @heather999, have you had some time to look at this? Thank you

[heather999]

Looking at it now! I find part of the issue is that there is old code under snmachine/utils/archive which I believe is no longer relevant. I am moving that archive directory aside and placing it back at the top-level of this repo.. then I am able to do a editable pip install using this copy of the code and run some of the example notebooks... with some minor modification now that utils is a subpackage of snmachine. So I am modifying things to look like:
from snmachine.utils.plasticc_pipeline import get_directories, load_dataset
I recall you didn't need to do that when you tested against the original PR, but I still think that is necessary. I'll update the PR and we can both test this out again (and hopefully finally close this!)

[Catarina-Alves]

Solved by #259