Auto-format Python sources with black, fix all issues reported by flake8 (#1010)

* Update config for black and flake8
* Auto-format Python sources with black
* Fix issues reported by flake8
* Exclude protobuf files from black
* Address formatting feedback

python/oled/src/interrupt_handler.py

@@ -8,6 +8,7 @@ class GracefulInterruptHandler:
     """
     Class for handling Linux signal interrupts
     """
+
     def __init__(self, signals=(signal.SIGINT, signal.SIGTERM)):
         self.signals = signals
         self.original_handlers = {}