[0025] [ndf-script] [debt] Clean variables

Check each variables in the project and apply the following guidelines:

Must be ASCII compatible
Private variables should have the double underscore prefix, ex: __variable
Protected variables should have the underscore prefix, ex: _variable
Constants should adopt the UPPER_SNAKE_CASE namming convention, ex: MY_CONSTANT
Variables (Private, protected, public and global) should adopt the snake_case namming convantion, ex: my_variable
Never abbreviate variables name, ex: my_var non-compliant -> my_variable compliant
Variables with a sigle letter are allowed only for a looping context, ex: loop counters

greg-ynx / NexusDownloadFlow