move operators and assembling routines to DOFMatrixBase and DOFVectorBase

4 jobs for feature/operators_in_dofmatrix in 19 minutes and 12 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
passed #6690
debian:10 clang-6-libcpp-17

00:19:12

passed #6689
debian:10 gcc-8-17

00:12:18

passed #6691
debian:9 gcc-6-14

00:11:34

passed #6692
ubuntu:18.04 clang-6-17

00:17:04