Take Screenshot hotkey and separate folder for screenshots and split images

[Avasam]

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

When building a split image folder, I like to take several images at a time to evaluate good candidates for split points, and then mask the selected image as needed before inserting it into my actual series of split images.

Describe the solution you'd like

I think this flow would be easier if I could bind a key to taking a screenshot (preferably without opening the image immediately), as well as set a separate folder path where these images would be saved, so they wouldn't clutter my in-progress split image folder with images that I probably won't use.

Describe alternatives you've considered
N/A

Additional context
Copied from Avasam#59

[Avasam]

Comment copied from Avasam#59 (comment)

I don't mind adding a screenshot hotkey, I think it makes sense.
I don't think there's a canonical screenshot shortcut for apps, so I'd probably add it to AutoSplit's hotkey system (it's easy to do since I last refactored it anyway) rather than a Qt shortcut.

I can also add a config textfield to select an alternate screenshot path (defaults to the splits images path if empty). I could see myself using it as well.

Finally, I'm not sure if I'd want the behaviour of opening screenshots to be different between the hotkey and the button. Or if I'd rather have it be configurable. (both reusing the same config)

[Avasam]

Decided to also implement the option to not open the file. I'm not a huge fan of how there's no indication that a screenshot has been taken when using the hotkey, but it's optional and probably know what you're doing at that point. I can improve later.
For example, I might wanna consider offering to open the containing folder instead. And toast/notification system.