WIP: Resolve "Add virtual refinement for VTK output"

What does this MR do?

Uses the subsampling writer to produce virtual refinement in the vtk output

Can this MR be accepted?

• Implemented
• Added/Updated tests:
  • Add virtual_refinement option to old tests
  • Compare size of vtk outputs
• Pipelines passing
  • 
  • 
  • 
• Delete branch option set
• Added entry to CHANGELOG.md

Related issues

Closes #14