Add warning to Downloads dropdown

[adswafford]

Since the file is 5.1 GB file, it is worth warning users who try to download it? Or include the size of the file in the dropdown information box as a heads-up

[danteese]

Do we need to add sort of modal when the user tries to download?

[antgonza]

A modal will be great but a confirm box will also do it.

[antgonza]

closed by #2372