Merge pull request #12411 from jppelteret/fe_interface_values_02

FEInterfaceValues: Make class interfaces consistent with FEValues and its views

diff --cc include/deal.II/fe/fe_interface_values.h
Simple merge

diff --cc tests/feinterface/fe_interface_values_02.cc
Simple merge

diff --cc tests/feinterface/fe_interface_values_03.cc
Simple merge

diff --cc tests/feinterface/fe_interface_values_06.cc
Simple merge

diff --cc tests/feinterface/fe_interface_values_07.cc
Simple merge

diff --cc tests/feinterface/fe_interface_values_08.cc
Simple merge

diff --cc tests/feinterface/fe_interface_values_09.cc
Simple merge