Simplify Solvers

[joaquimg]

Close #165
Close #172
Close #182

[codecov]

Codecov Report

Merging #196 (78c21c6) into master (833b023) will increase coverage by 8.84%.
The diff coverage is 92.59%.

@@            Coverage Diff             @@
##           master     #196      +/-   ##
==========================================
+ Coverage   80.52%   89.36%   +8.84%     
==========================================
  Files           8        8              
  Lines         837      837              
==========================================
+ Hits          674      748      +74     
+ Misses        163       89      -74     

Impacted Files	Coverage Δ
src/moi_wrapper.jl	85.22% <92.59%> (+28.03%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 833b023...78c21c6. Read the comment docs.

[joaquimg]

MOI Unit tests commented out:

                "test_conic_linear_VectorOfVariables_2",
                "test_attribute_SolverVersion",

Suggestions for solver version? inner solver? diffopt version? both?
ex: "DiffOpt=x.y.z with $(solvername)=a.b.c"?

conic_linear error is:

test_conic_linear_VectorOfVariables_2: Error During Test at C:\Users\joaquimgarcia\.julia\packages\MathOptInterface\FHFUH\src\Test\test_conic.jl:357
  Test threw exception
  Expression: ≈(MOI.get(model, MOI.ConstraintDual(), vs), T[7], config)
  ArgumentError: Bridge of type `MathOptInterface.Bridges.Variable.ZerosBridge{Float64}` does not support accessing the attribute `MathOptInterface.ConstraintDual(1)`. If you encountered this error unexpectedly, it probably means your model has been reformulated using the bridge, and you are attempting to query an attribute that we haven't implemented yet for this bridge. Please open an issue at https://github.com/jump-dev/MathOptInterface.jl/issues/new and provide a reproducible example explaining what you were trying to do.
  Stacktrace:
    [1] get(#unused#::MathOptInterface.Bridges.LazyBridgeOptimizer{HiGHS.Optimizer}, attr::MathOptInterface.ConstraintDual, bridge::MathOptInterface.Bridges.Variable.ZerosBridge{Float64})

[joaquimg]

@blegat and @matbesancon, for me we can tag a new version as soon as we merge this. Also probably fine merging even with those two excludes.

[matbesancon]

I'll let @blegat take a look at the last error before merging. The SolverVersion attribute is not urgent