Correcting header in tabulatedNTUHeatTransfer from fileName to file

Fixing humidityTemperatureCoupled problem in parallel
Adding Allrun-parallel to externalSolarLoad and windshieldCondensation tutorials

- A few without a 'cd' at the start.
  Use $(getApplication) directly in more places (for clarity).

- A few without a 'cd' at the start.
  Several remove files that are already covered by the cleanCase function.

- makes it easier to ensure the correct behaviour, consistently

radiationProperties: general model organization
fvOptions: taking out the use of pressureJumpDirec.... from tutorial

This bc was in compressible turbulence library which made it dependent
on liquidProperties. It was moved to a separate library since it is only
used in a single tutorial.

ENH: Adding humidityTemperatureCoupledMixed BC and directionalPressureGradientExplicitSource and the corresponding tutorial
tutorials/heatTransfer/chtMultiRegionFoam/windshieldCondensation