[Depends on #3695] Observer gurobi refactor

[michaelbynum]

Summary/Motivation:

This PR refactors the gurobi interfaces to achieve two goals:

• reduce duplicate code
• use the new contrib.observer package

Changes proposed in this PR:

• create a directory for gurobi now that there are 3 files
• create a base class for all of the interfaces that use gurobipy, making the direct and persistent interfaces more consistent (e.g., tc_map, postsolve, solve, mipstart)
• modify the persistent interface to use the contrib.observer package
• add mipstart functionality to gurobi direct
• add a minimum gurobipy version to the direct interface (addMConstr was not added until version 9)
• extract some of the code out of the persistent interface to create a direct interface that can be used without the overhead of the observer
• simplified some of the persistent interface

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

❌ Patch coverage is 90.01289% with 155 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.97%. Comparing base (2ca7dfb) to head (cfa8633).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
...contrib/solver/solvers/gurobi/gurobi_persistent.py	89.82%	80 Missing ⚠️
pyomo/contrib/observer/model_observer.py	88.25%	58 Missing ⚠️
...ontrib/solver/solvers/gurobi/gurobi_direct_base.py	91.05%	11 Missing ⚠️
...omo/contrib/solver/solvers/gurobi/gurobi_direct.py	96.39%	4 Missing ⚠️
pyomo/contrib/observer/component_collector.py	94.28%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3698      +/-   ##
==========================================
+ Coverage   85.94%   87.97%   +2.03%     
==========================================
  Files         892      895       +3     
  Lines      103018   103616     +598     
==========================================
+ Hits        88535    91156    +2621     
+ Misses      14483    12460    -2023     

Flag	Coverage Δ
builders	26.75% <22.87%> (+0.02%)	⬆️
default	85.79% <89.81%> (?)
expensive	34.04% <23.00%> (?)
linux	69.98% <43.26%> (-15.87%)	⬇️
linux_other	69.98% <43.26%> (?)

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