Remove sardanaeditor
Sardana editor has low popularity (see Sardana Users Questionnaire 2020), is buggy (there are 14 opened issues) and there are no resources to maintain it. Furthermore, with the constantly evolving Spyder API it is very painful to maintain it operational. After an agreement on the Sardana follow-up meeting proceed to remove it.
We also agreed to close the following related 14 opened issues.
As we agreed the documentation will still list this widget with the following warning:
I will auto-merge if there are no objections.