Let user define the output field name in the wallShearStress FO

Functionality to add/problem to solve

Would it be OK to extend the functionality of the wallShearStress FO to support other output field names rather than wallShearStress? The latter would still be the default, thus not braking any workflows or tutorials.

I realize that not a lot of people will need that, but I guess it cannot hurt? The reason I want this implemented is that my WMLES library also uses wallShearStress, and if one also uses the FO, there is a name collision, which leads to a nasty looking crash, as discovered by Tobias.

Proposal

Add an optional field or fieldName keyword for the user to set, and use that in the constructor, which allocates the volVectorField.

Funding

I am reasonably sure I can implement this myself without any help. Impact on code maintenance should be negligible.