Format files with black

- Format all files with black
- Update tox.ini flake8 arguments to be compatible
- Add black to requirements-extra.txt
- Reduce ignored flake8 rules and fix a few violations

core/se/scanner.py

@@ -8,6 +8,7 @@ from hscommon.trans import tr
 
 from core.scanner import Scanner as ScannerBase, ScanOption, ScanType
 
+
 class ScannerSE(ScannerBase):
     @staticmethod
     def get_scan_options():
@@ -16,4 +17,3 @@ class ScannerSE(ScannerBase):
             ScanOption(ScanType.Contents, tr("Contents")),
             ScanOption(ScanType.Folders, tr("Folders")),
         ]
-