DirichletBC: Use specialization for Constraints instead of general case

src/amdis/DirichletBC.inc.hpp calls

34: auto columns = Constraints<Mat>::dirichletBC(matrix, dirichletNodes_);

There are specializations for this in the LinAlg implementations, yet only the generic implementation is included in the file.

This MR replaces the generic include <amdis/linearalgebra/Constraints.hpp> with the specialization in <amdis/linearalgebra/*/Constraints.hpp>. This is already done in src/amdis/PeriodicBC.inc.hpp.

src/amdis/DirichletBC.inc.hpp

@@ -7,8 +7,7 @@
 #include <dune/functions/functionspacebases/interpolate.hh>
 #include <dune/functions/functionspacebases/subspacebasis.hh>
 
-#include <amdis/Output.hpp>
-#include <amdis/linearalgebra/Constraints.hpp>
+#include <amdis/LinearAlgebra.hpp>
 
 namespace AMDiS {