ARMI has first-order dependencies that are not declared in our pyproject.toml

[john-science]

Okay, ARMI is not declaring these runtime first-order dependencies, because (I am guessing) they are also second-order dependencies. But I consider this a failure of documentation:

• python-dateutil - used in armi/utils/parsing.py
• mpl_toolkits - NVM, this is part of mat-props

Similarly, ARMI is not declaring this first-order test dependence:

• nbformat - used in test_historyTracker.py and test_notebooks.py

Lastly, ARMI has two dependencies that I find suspect because we are importing an ENTIRE dependency for one function:

• pyDOE - only used in one place
• python-dateutil - only used once, to read datetime strings slightly more easily.

[john-science]

As a historical note, I first did this research because @drewj-tp opened a ticket, and I thought to do a little digging in a more general context.