further fixes of py3 issues

complaints by pylint are mainly related to
- remove object from base list in class definitions
- unnecessary else/elif after return/raise

Change-Id: I13d15449149cc8bba0562338d0c9c42e97163bdf
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/21325
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

bin/cfg-editor

@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+# pylint: disable=invalid-name
 #  -*- coding: utf-8 -*-
 # *****************************************************************************
 #

bin/secop-console

@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+# pylint: disable=invalid-name
 #  -*- coding: utf-8 -*-
 # *****************************************************************************
 #
@@ -21,7 +22,6 @@
 #
 # *****************************************************************************
 
-import os
 import sys
 import argparse
 from os import path

bin/secop-server

@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+# pylint: disable=invalid-name
 #  -*- coding: utf-8 -*-
 # *****************************************************************************
 #
@@ -22,7 +23,6 @@
 #
 # *****************************************************************************
 
-import os
 import sys
 import argparse
 from os import path