[Feature] Add Save Colour Settings Functionality

[tmeyer-smith]

Currently, every time you load the application the colour settings are set to the default black. However, if you prefer another colour theme you have to change it every time you use the app. It would be useful to be able to save your theme settings.

[tmeyer-smith]

@softeng-701

[softeng-701]

@tmeyer-smith Approved