Add a custom field for the screenshot folder

[meilleur102]

I dont know why but the folder that was created in my Document was Escape from Tarkov and the app was looking for Escape From Tarkov (capital F on From)
I add no error but the screenshot / map location was not working. Instead of just changing the code locally for me I add the same kind of field for a custom screenshot folder (like you did for the custom logs folder)

Some refactor was done cause of the IDE setting so you can modify as you wish

[Razzmatazzz]

That's for this PR. It looks like it includes the code for setting a custom screenshot folder, but I'm not seeing where the app is using that new value to detect screenshots.