Add gurobi_direct implementation to contrib.solver

[jsiirola]

Fixes # .

This PR builds on (and includes) PR #3224

Summary/Motivation:

This provides a implementation of the gurobi_direct solver for the new contrib.solver package. The interface makes use of the standard_form writer to send the entire model to Gurobi as a single matrix. As a result, it is reasonably performant (on one huge test, it almost got within ~2x of COEK).

Like all solvers in contrib.solver, this is still a work in progress. I am opening a PR so that others can begin to poke it.

There are still several missing features, including:

• support for warmstart
• support for quadratic objectives / constraints

Changes proposed in this PR:

• add the pyomo.contrib.solver.gurobi_direct solver
• Improvements to standard_form_
  • return list of Objectives as well as the objective constant offset
  • gracefully handle models with no objective or no constraints
  • add option to control how the objective sense is mapped (or not)

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

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

Attention: Patch coverage is 95.23810% with 17 lines in your changes are missing coverage. Please review.

Project coverage is 88.41%. Comparing base (c68ce66) to head (9790e08).

Files	Patch %	Lines
pyomo/contrib/solver/gurobi_direct.py	93.92%	15 Missing ⚠️
pyomo/solvers/plugins/solvers/CPLEX.py	85.71%	1 Missing ⚠️
pyomo/solvers/plugins/solvers/SCIPAMPL.py	75.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3225      +/-   ##
==========================================
+ Coverage   88.40%   88.41%   +0.01%     
==========================================
  Files         847      849       +2     
  Lines       95285    95585     +300     
==========================================
+ Hits        84232    84511     +279     
- Misses      11053    11074      +21     

Flag	Coverage Δ
linux	86.36% <93.27%> (+0.02%)	⬆️
osx	76.24% <92.15%> (+0.06%)	⬆️
other	86.56% <93.27%> (+0.01%)	⬆️
win	83.86% <92.71%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[mrmundt]

Leftover line?