KDE Review OptiImage

Hi,

After writing the initial commit back in 2021 and several rewrite (hello Rust, 
goodbye Rust 😅), I finally finished working on a new app: OptiImage.

It's a GUI wrapper for a few tools: oxipng, jpegoptin, scour, cwebp to 
compress images. It's relatively basic and inspired by the following GNOME 
app: https://apps.gnome.org/Curtail/

Here is the issue to track the kde review
https://invent.kde.org/graphics/optiimage/-/issues/2

I already fill all the trivial checkbox: e.g. CI running and reuse conformance. 
Clazy is unfortunately not working due to the lack of compiler support for 
coroutines in clazy.

Cheers,
Carl