DBI utils module - Githubissues

Proposal by @andrea-pasquale:

Concerning utils_* we could also think about turning it into a module. Something like

utils/
    __init__.py
    analytical.py
    gradients.py
    scheduling.py

[ ] dbi.utils.groupcommutators.py could hold helper functions for evaluating bounds and using that for testing
[ ] I'd like the active people to prioritize other things but I'll keep this in a timeline and delegate either to Sam or someone new entering because can be a nice warmup task
@wrightjandrew FYI

qiboteam / qibo