Move linear_solver documentation.

Applications/ApplicationsLib/ProjectData.cpp

Documentation/ProjectFile/i_ProjectFile.md

Documentation/ProjectFile/linear_solver/c_linear_solver.md

...tation/ProjectFile/prj/linear_solvers/i_linear_solvers.md

...ectFile/prj/linear_solvers/linear_solver/eigen/i_eigen.md

...j/linear_solvers/linear_solver/eigen/t_error_tolerance.md

...inear_solvers/linear_solver/eigen/t_max_iteration_step.md

...e/prj/linear_solvers/linear_solver/eigen/t_precon_type.md

...tFile/prj/linear_solvers/linear_solver/eigen/t_scaling.md

...e/prj/linear_solvers/linear_solver/eigen/t_solver_type.md

...tFile/prj/linear_solvers/linear_solver/i_linear_solver.md

...ectFile/prj/linear_solvers/linear_solver/petsc/i_petsc.md

...le/prj/linear_solvers/linear_solver/petsc/t_parameters.md

...ctFile/prj/linear_solvers/linear_solver/petsc/t_prefix.md

...ion/ProjectFile/prj/linear_solvers/linear_solver/t_lis.md

...on/ProjectFile/prj/linear_solvers/linear_solver/t_name.md

...prj/nonlinear_solvers/nonlinear_solver/t_linear_solver.md

MathLib/LinAlg/Eigen/EigenLinearSolver.cpp

MathLib/LinAlg/Lis/LisOption.h

MathLib/LinAlg/PETSc/PETScLinearSolver.cpp