Apply official python naming conventions

[paulober]

Describe the bug
Many local variables have names like MyVariable or sth like that, but the naming conventions of python say: my_variable
Most of the functions and methods also are not named like this: def my_function_is_great()

To Reproduce

1. for example GenericTelemetry.py line 59
2. a method example: GenericTelemetry.py line 53

Expected behavior
A clear and concise description of what you expected to happen.

Code snips

1. def displayTelemetryItem(self, datagram, tlmIndex, labelField, valueField):
2. TlmField1 = tlmItemFormat[tlmIndex]

Additional context
https://www.python.org/dev/peps/pep-0008/