[Feature Request] Have "Export Selected" prompt if it should overwrite an existing file

[SuperFromND]

Is your feature request related to a problem? Please describe.
Currently, when you select a bunch of files (such as a bunch of .TPLs in a .ARC) and export them to a folder, if any of the files happen to already exist in the destination folder, BrawlCrate will just silently overwrite them with zero indication or user feedback that it's done this. This isn't particularly great, as many other programs with export or file-writing functions will prompt you if it wants to overwrite an existing file.

Describe the solution you'd like
Check if the currently-exporting file already exists, and if it does, pop up a window asking if it should be overwritten, with options of "Yes" (just overwrite it) and "No" (skip the file and move on to the next one).

I think there should also be some form of "Keep Both" option in the prompt, where the newly-exported file would have something added to it as a a suffix (e.g. you're exporting a file called foobar.png, and if you select "Keep Both" it exports as foobar-01.png instead), and a "Do this for all exports" setting (either in the window or in BrawlCrate's preferences), which is fairly self explanatory.

Essentially, think: the functionality from the Windows "Copy File" window (assuming that we can't just directly use that window using some sort of Windows API call, at least for Windows builds of BrawlCrate):