ENH: chtMultiRegionFoam: solve single h equation

...ions/solvers/heatTransfer/chtMultiRegionFoam/Make/options

...cations/solvers/heatTransfer/chtMultiRegionFoam/allhEqn.H

...vers/heatTransfer/chtMultiRegionFoam/chtMultiRegionFoam.C

...solvers/heatTransfer/chtMultiRegionFoam/createAllFields.H

...s/solvers/heatTransfer/chtMultiRegionFoam/createAllMesh.H

...tMultiRegionFoam/fluid/compressibleMultiRegionCourantNo.H

...heatTransfer/chtMultiRegionFoam/fluid/createFluidFields.H

...heatTransfer/chtMultiRegionFoam/fluid/createFluidMeshes.H

...eatTransfer/chtMultiRegionFoam/fluid/initContinuityErrs.H

.../solvers/heatTransfer/chtMultiRegionFoam/fluid/mapFluid.H

...solvers/heatTransfer/chtMultiRegionFoam/fluid/rmapFluid.H

...tTransfer/chtMultiRegionFoam/fluid/setRegionFluidFields.H

...fer/chtMultiRegionFoam/fluid/solvePressureVelocityFluid.H

...vers/heatTransfer/chtMultiRegionFoam/readPIMPLEControls.H

applications/solvers/heatTransfer/chtMultiRegionFoam/rmap.H

...s/solvers/heatTransfer/chtMultiRegionFoam/rmapTemplates.C

...heatTransfer/chtMultiRegionFoam/solid/createSolidFields.H

...heatTransfer/chtMultiRegionFoam/solid/createSolidMeshes.H

.../solvers/heatTransfer/chtMultiRegionFoam/solid/mapSolid.H

...solvers/heatTransfer/chtMultiRegionFoam/solid/rmapSolid.H