Updates HyTeG forms for epsilon operator variants
The merge reduces the number of form files. The hyteg-form-generator now allows to generate single [ch]pp files for forms that are composed of different scalar sub-forms. This merge replaces the separate
p[12]_epsilon[cc|var]_[012]_[012]_[affine|blending].[ch]pp
files by newly generated single
p[12]_epsilon[cc|var]_[affine|blending].[ch]pp
files. It also updates
p[12]_epsilon_all_forms.hpp
and changes the corresponding header inclusions in the operator sources.