[widgets][experimenteditor] Implement ExperimentEditor

This version currently doesn't apply input/output checks.
4 jobs for 185_experiment_editor in 13 minutes and 29 seconds (queued for 7 seconds)
Status Job ID Name Coverage
  Build
passed #174497
docker
build_linux_36

00:12:18

passed #174498
docker
build_linux_37

00:12:42

passed #174495
macosx
build_macosx_36

00:07:22

passed #174496
macosx
build_macosx_37

00:13:29