Albany::Application, add distParamLib in the dirichlet workset to enable
dirichlet boundary conditions based on distributed parameters
Added PHAL::DirichletField, to implement dirichlet boundary conditions
prescribing a field. The field need to be a distributed parameter whose
vector has the same map of the solution vector.
Albany::PHAL_FactoryTraits. Added boundary dirichlet_field bc to the
factory traits.
Albany::BCUtils. Added boundary condition dirichlet_field to bc
utilities.

If "dirichlet_field" has been registered as a nodal distributed
parameter in the problem, then it is possible to prescribe the dirichlet
condition adding this line to input file (in the Dirichlet BCs section)

<Parameter name="DBC on NS nodsetname for DOF dofName prescribe Field"
type="string" value="dirichlet_field"/>
FELIX::StokesFO, just added a commented line for future convenience.
PHAL::DirichletField, fix the SG implementation