Merge branch 'RunFunctions' into 'merge-foundation'

ENH: added -decomposeParDict as argument to getNumberOfProcessors()

Continuing discussion at 
https://develop.openfoam.com/Development/OpenFOAM-plus/commit/1507178a1bfffef916faab8f6d69dd72c3f0ee76?title=#note_1093

Now the Allrun script could be
```
runParallel -decomposeParDict system/decomposeParDict-6 snappyHexMesh -overwrite
```

Thanks @Mattijs 


See merge request !36