[789-deprecate-content-of-globaldefinitions] string -> std::string

src/CardiacData.cpp

src/CardiacData.hpp

src/MainElphy.cpp

src/cellmodels/MCellModel.cpp

src/cellmodels/MCellModel.hpp

src/cellmodels/solvers/MElphySolver.cpp

src/cellmodels/solvers/MElphySolver.hpp

src/cellmodels/solvers/MTensionSolver.cpp

src/cellmodels/solvers/MTensionSolver.hpp

src/coupled/MainCoupled.cpp

src/coupled/MainCoupled.hpp

src/coupled/problem/CoupledBenchmarkProblems.hpp

src/coupled/problem/CoupledProblem.cpp

src/coupled/problem/CoupledProblem.hpp

src/coupled/problem/DeformedProblem.hpp

src/coupled/problem/PhysiologicalProblems.hpp

src/elasticity/MainElasticity.cpp

src/elasticity/MainElasticity.hpp

src/elasticity/MultiDiscElasticity.hpp

src/elasticity/assemble/DGElasticity.cpp