Finish upwind SBP implementation

[ranocha]

The first experimental version is implemented in #1275.

TODO

• allow periodic FDSBP operators #1570
• Remove all !!! warning "Experimental implementation (upwind SBP)"
• Clean-up the SaveSolutionCallback such that it works smoothly with FDSBP methods. See comment

  # TODO: This is hack to enable the FDSBP solver to use the
  #       `SaveSolutionCallback`.

• Enhance and clean-up visualization pipeline; for VTK style viz see here. Direct visualization in a REPL session requires modification to recipes for Plots or Makie.
• Mention postprocessing in the tutorial once the corresponding Trixi2Vtk.jl updates are finished (Add capability to not perform reinterpolation  Trixi2Vtk.jl#57)
  • Remember to pass reinterpolate = false, data_is_uniform = true to trixi2vtk!
  • Store the nodes additionally so that passing data_is_uniform is not required anymore?
• From Upwind finite difference SBP solver #1275 (comment): "The only thing you might want to consider is adding the FDSBP solver to the table in https://trixi-framework.github.io/Trixi.jl/stable/overview/#Semidiscretizations, maybe with a footnote that it still experimental."
• De-aliased VolumeIntegralStrongForm, see Curvilinear FDSBP #1295 (comment) and Upwind SBP on curved meshes #1857
  • Remove restriction xmin = -1, xmax = 1 for curved meshes (see Upwind SBP on curved meshes #1857 (comment))

See also #607