Start moving settingsValidation to the settings area

[john-science]

What is the change?

I have moved armi/operator/settingsValidation.py to armi/settings/settingsValidation.py, where it obviously belongs.

Why is the change being made?

Unfortunately, this would be a breaking change for like 6 downstream projects that I can see. So, for this first pass, I am not breaking the API, but adding in some backwards compatibility-saving tools.

I will try to update those downstream projects over the next few months, so we can make this change permanent.

But, for now, we need the backwards compatibility-saving temp module.

This is a first step in: #1880

---

Checklist

• This PR has only one purpose or idea.
• Tests have been added/updated to verify any new/changed code.

• The code style follows good practices.
• The commit message(s) follow good practices.

• The release notes have been updated if necessary.
• The documentation is still up-to-date in the doc folder.
• The dependencies are still up-to-date in pyproject.toml.

[drewj-tp]

I've confirmed the only diff between a git mv armi/operators/settingsValidation.py armi/settings is the lack of Query.__nonzero__

$ git mv .\armi\operators\settingsValidation.py .\armi\settings\
$ git diff --staged origin/settingsValidation_deprecate_move --  .\armi\settings\settingsValidation.py
diff --git a/armi/settings/settingsValidation.py b/armi/settings/settingsValidation.py
index ed11f5b3..324f2300 100644
--- a/armi/settings/settingsValidation.py
+++ b/armi/settings/settingsValidation.py
@@ -101,6 +101,8 @@ class Query:
             )
             raise

+    __nonzero__ = __bool__  # Python2 compatibility
+

Which is very okay.

Doc nit to render properly in the deprecated file and then we're good.