[Feature Request] Display EVEN amount of page thumbnails in a single row

[githubuser181226]

Is your feature request related to a problem? Please describe.

Hello.

In fullscreen maximized window NAPS2 sometimes shows ODD number of thumbnails in a single row, which is most certainly not optimal when reviewing duplex scanning results.

You have to unmaximize and set the size of the window manually to see even number of pages in a row.

Please consider my suggestion to change that.
Thank you.

Describe the solution you'd like
I want an option to set a specific amount of thumbnails always displayed no matter the window size and zoom level.

Describe alternatives you've considered
Alternatively make it so the program always wraps around each row of thumbnails at an EVEN amount NO MATTER the window size nor zoom level.

Additional context
n/a