Add support for Xpress callbacks in Pyomo

[jsiirola]

Fixes # .

Summary/Motivation:

This is reopening #2648

Changes proposed in this PR:

• Add a base class and callback implementations for providing users access to the Xpress callback mechanism

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

@djunglas - New PR is here!

[codecov]

Codecov Report

Attention: Patch coverage is 80.14440% with 55 lines in your changes are missing coverage. Please review.

Project coverage is 86.75%. Comparing base (0ef8cde) to head (ae3e3a3).
Report is 3787 commits behind head on main.

Files	Patch %	Lines
pyomo/solvers/plugins/solvers/xpress_direct.py	80.14%	55 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2714      +/-   ##
==========================================
- Coverage   86.80%   86.75%   -0.06%     
==========================================
  Files         766      766              
  Lines       86041    86307     +266     
==========================================
+ Hits        74690    74875     +185     
- Misses      11351    11432      +81     

Flag	Coverage Δ
linux	83.86% <80.14%> (-0.41%)	⬇️
osx	73.70% <80.14%> (+0.02%)	⬆️
other	84.04% <80.14%> (-0.40%)	⬇️
win	81.63% <80.14%> (+<0.01%)	⬆️

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