Network check fixes

- Proper network mapping
- Proper reclass lookup
- VIP detection
- Simple error gathering
- IP shown as 'exploded', i.e. in CIDR format
- MTU matching and detection
- Errors class for handling errors, including codes and indices
- Summary and detailed errors view
- Flake8 refactoring

Change-Id: I8ee37d345bdc21c7ad930bf8305acd28f8c121c8
Related-PROD: PROD-28199
diff --git a/cfg_checker/common/log.py b/cfg_checker/common/log.py
index 9b29ba4..6edac2f 100644
--- a/cfg_checker/common/log.py
+++ b/cfg_checker/common/log.py
@@ -1,5 +1,5 @@
-import os
 import logging
+import os
 
 pkg_dir = os.path.dirname(__file__)
 pkg_dir = os.path.join(pkg_dir, os.pardir, os.pardir)
@@ -85,6 +85,7 @@
 
     return logger, logger_cli
 
+
 # init instances of logger to be used by all other modules
 logger, logger_cli = setup_loggers(
     'cfg_checker',