add shortcuts zot(), fot(), and sot() for backward compatibility/similarity with old AMDiS

4 jobs for feature/make_operator_shortcuts in 37 minutes and 35 seconds (queued for 33 minutes and 50 seconds)
Status Job ID Name Coverage
  Test
passed #8648
debian:10 clang-6-libcpp-17

00:25:01

passed #8647
debian:10 gcc-8-17

00:18:16

passed #8649
debian:9 gcc-6-14

00:19:11

passed #8650
ubuntu:18.04 clang-6-17

00:23:44