Make the code compatible with OSQP v1.0.0

[gergondet]

This PR updates osqp-eigen to be compatible with OSQP v1.0.0 (currently in beta). I have kept the API of osqp-eigen (almost) identical

The following things are known to not work (and afaik cannot be done with OSQP v1.0.0)

• bool OsqpEigen::Solver::getPrimalVariable(Eigen::Matrix<T, n, 1> &dualVariable) and bool OsqpEigen::Solver::getDualVariable(Eigen::Matrix<T, m, 1> &dualVariable) return the solution held in the solution rather than the values in the workspace (which are not accessible anymore)
• bool OsqpEigen::Solver::clearSolverVariables() is a no-op since workspace is opaque now

Otherwise I can at least confirm the unit tests pass but I haven't tried much more.

[traversaro]

Thanks a lot @gergondet ! fyi @GiulioRomualdi @S-Dafarra

[traversaro]

Sorry for the unrelated CI failure, it should be fixed by https://github.com/robotology/osqp-eigen/pull/133 .

[gergondet]

Thanks @traversaro

I have rebased on the lastest master and it all seems green now (the latest Windows failure is a network hiccup I guess)

The Codacity warnings are wrong, the members are used since the structure replaces the OSQPData structure from the old API

[GiulioRomualdi]

Thank you @gergondet! Your work is much appreciated, and we're grateful for the time and effort you put into it! I want to apologize for the long delay in reviewing and merging your PR.