Add delete confirmation modal in ImageManager

[jumbosushi]

What behavior were you expecting?

When I click delete button in ImangeManager from ArticleEditors, I expect to see delete confirmation modal.

ImageManager delete button in ArticleEditor

/images/ delete confirmation modal example

What actually happened?

No delete confirmation modal popped up. This could lead to images being deleted accidentally

Steps to reproduce

(Try this in your local server NOT on prod)
0. Go to /admin/articles/new

1. Click on Featured Image Tab
2. Click "Select Image" to open ImageManager
3. Try to delete any image

What was your environment like?

Google Chrome 74.0.3729.157 on Ubuntu 16.04 LTS

Getting Started

Look at how <ConfirmButtom/> (code link) is being used in <ListItemToolbar/> component (code link)