v0.26 - Data visualization Settings

Added:

added a settings tab for all of the settings
added function that makes windows open in the middle of the screen
added button that opens a random window when is pressed
added many settings:
font sizes - normal, big, large
transparency of the window(s)
topmost for the main window
open windows in the middle of the screen
make the windows resizable or not
fun numbers settings - random numbers (and sometimes characters) for every "data visualization" main input entries

Improved:

window sizes are determined by the widget and not by a pre-defined value
when you close the main window all the additional windows will be closed as well
every window has gone through (small) improvement in the placement of the widgets
combo boxes are now read-only so you can't accidentally write in them
every combo box have a default value

Fixes:

deleted some combo boxes values had values that weren't working
fixed some values errors

Code quality:

optimized imports
made many repetitive functions into a single one:
get transparency
get legend
change marker
change line
made many repetitive values into global variables:
main title font
subtitle font
bold title font