Resolve "Add DG local operator to the SimulationTransport class"

What does this MR do?

This MR adds a local operator for the Discontinuous Galerkin method for the diffusion transport equation in the transport model. This local operator is based on the PDELab local operator for the convection-diffusion equation in the pdelab repository and adapted for the specific use case of DORiE. That is: usage of a velocity field provided by another operator and usage of the specific parameterizations for the transport process in unsaturated porous media. Additionally, it has an implementation for adaptivity which targets the diffusive part of the convection-diffusion equation (mainly copied from the Richards model). Edit: Adaptivity module removed from transport solver during review.

Is there something that needs to be double checked?

Is there a way to reduce code duplication?

Can this MR be accepted?

• Implemented ...
  • DG local operator
  • Implicit time-stepping
  • [ ] Implicit time-stepping parameters in config file
  • Default compilation on RORDER==TORDER
• Added/Updated tests:
  • Add higher orders to the constant transport test
• Added/Updated documentation
• Pipeline passing
• Squash option set
• Delete branch option set
• Added entry to CHANGELOG.md

Assignee: If the Squash option is set, check/update the commit message right before merging!

Related issues

Closes #111 (closed)