Allow preview of crop before saving

[bohall00]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the request will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.

Feature description

When cropping an image, there should be a way to apply the crop before saving so the user can verify they're satisfied with the result.

Why do you want this feature?

Difficulty with precise cropping has been discussed in other issues. As is, I hope for the best when cropping that I don't unintentionally crop out part of the desired portion or unintentionally leave a sliver of the background remaining. A user should be able to verify the result of an action without needing to save and leave the editor.

Additional information

This is Mango. Imprecise cropping resulted in still seeing part of my ex-girlfriend behind her, so I have to re-open the editor and try again.

I did look through cropping-related issues, apologies if this has been raised already.