feat: add an option to import/export Scrupdate configuration

[DanielKirshner]

Description

It would be very helpful to have an option to import or export the Scrupdate configuration file.
This would allow users to easily restore their settings after reinstalling their operating system or share their configuration with others.

Use cases

• Reinstalling the operating system
• Migrating to another computer
• Sharing configurations with other users

Thank you for this great software!

[MatanBright]

Thanks!

I will add it in the next update.