Resolve testing in Python 3.12 (manage pyutilib, distutils dependencies)

[jsiirola]

Fixes # .

Summary/Motivation:

This resolves an error first observed in Python 3.12 where PyUtilib installs but no longer imports cleanly (due to an import imp). This was causing an issue in Pyomo where the TempfileManager logic thought that PyUtilib was not available, but the tests found it to be present. This PR updates all checks for PyUtilib to go through pyomo.common.dependencies, so that everyone uses the same "truth" value for PyUtilib's availability.

As part of this rework, the new structure removes the pyutilib import from the module scope. As a result, PyUtilib is no longer imported as part of pyomo.environ. This (slightly) speeds up import pyomo.environ (~5%), and the PR removes pyutilib from the expected list of TPLs in the environment after the pyomo.environ import.

Changes proposed in this PR:

• Rework pyomo.common.tempfiles to use pyomo.common.dependencies to check for PyUtilib
• Remove import of pyutilib from pyomo.common.tempfiles module scope
• Remove pyutilib from the list of expected TPLs importedby pyomo.environ

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1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (de96bef) 88.09% compared to head (e3df7bd) 88.10%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3065      +/-   ##
==========================================
+ Coverage   88.09%   88.10%   +0.01%     
==========================================
  Files         774      774              
  Lines       91536    91537       +1     
==========================================
+ Hits        80635    80648      +13     
+ Misses      10901    10889      -12     

Flag	Coverage Δ
linux	85.45% <100.00%> (+<0.01%)	⬆️
osx	75.47% <78.26%> (+0.03%)	⬆️
other	85.63% <100.00%> (+<0.01%)	⬆️
win	82.81% <65.21%> (+0.04%)	⬆️

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