Removed steps are still shown when restarting

[mattias-arbin]

To reproduce.
Run a job with a few steps.
Stop Bauta.
remove some steps.
restart Bauta.
The removed steps are still shown in the step-flow view.

Expected: Removed steps should not be shown. The steps from the metadata should dictate which steps to be shown.

[mattias-arbin]

Realized that the problem is in the frontend. DOM elements must be properly cleaned up.