Add documentation for conversion of saves

[networkfusion]

Description

Add documentation that explains how to convert existing saves from other flashcart menus (such as the ED64) to allow an easier experiencing when switching from other flashcart menus.

Bonus would be to perform automatic conversion within the menu.

How to solve the problem

No response

Describe alternatives you've considered

No response

Additional context

It might well be a straight rename of the file, but have not tried.

[networkfusion]

Documention added, but keeping open for bonus effort.

[networkfusion]

Documentation seems to be sufficient, so closing.

[networkfusion]

At minimum, the following also needs adding to the docs

[networkfusion]

Closing again as document improved.