Fix capture_output management of logger file descriptors

[jsiirola]

Fixes #3210 .

Summary/Motivation:

This resolves an issue with how capture_output manages LogHandlers when they appear in LogStreams that capture_output is sending output to, as reported by #3210. The root cause was a subtle interaction between Pyomo's default log handler (an instance of pyomo.common.log.StdoutHandler) and the log handler interception used by capture_output. In that situation, the default Pyomo LogHandler was resetting the handler's stream attribute back to the current value of sys.stdout when records were emitted by the handler. This led to capture_output trying to fetch and close the wrong file descriptor on exit.

This PR makes several changes to resolve this situation

• Update the Redirector classes used by capture_output to explicitly store the file descriptors they open and not rely on the stream to store the fd for them.
• Update the StdoutHandler class to not permanently change the output stream within the emit / flush methods.
• Switch Pyomo to not use the StdoutHandler and instead now just use a standard streamHndler.
• Update online docs so that modules can define a doctest setup functio that will be called for all documentation generated by autosummary.

Changes proposed in this PR:

• (see above)

Legal Acknowledgement

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1. I agree my contributions are submitted under the BSD license.
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.92%. Comparing base (dc503c2) to head (1922d28).
Report is 14 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3633   +/-   ##
=======================================
  Coverage   88.92%   88.92%           
=======================================
  Files         888      888           
  Lines      102347   102363   +16     
=======================================
+ Hits        91009    91026   +17     
+ Misses      11338    11337    -1     

Flag	Coverage Δ
builders	26.68% <14.28%> (-0.01%)	⬇️
default	85.51% <92.85%> (?)
expensive	34.04% <14.28%> (?)
linux	86.73% <100.00%> (-1.95%)	⬇️
linux_other	86.73% <100.00%> (+<0.01%)	⬆️
osx	83.03% <100.00%> (+<0.01%)	⬆️
win	84.94% <100.00%> (+<0.01%)	⬆️
win_other	84.94% <100.00%> (+<0.01%)	⬆️

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