Add an option for drop shadows, for windows

[Lunchb0ne]

It would be really nice if there could be an option for adding drop shadows to screenshots taken of windows, like how it's done on something like MacOS.

I feel like that would be a nice feature and really adds to the screenshot. Especially now that Windows 11 forces round corners on windows, maybe this can be used

[Geeyun-JY3]

This feature needs PRO: https://docs.snipaste.com/changelog?id=new-pro-features

[Geeyun-JY3]

Duplicate of #197