Updates HyTeG forms for epsilon operator variants
The hyteg-form-generator now allows to generate single [ch]pp files for forms that are composed of different scalar sub-forms. This commit 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 udpates p[12]_epsilon_all_forms.hpp and changes the corresponding header inclusions in the operator sources.