Delete button to delete broken themes

[ideag]

At the moment (in 3.9) there is no way for the user to remove a broken theme via Admin Panel.

User can remove a valid theme, but if theme installation failed due to bad internet connection, server timeouts, etc. the only way to remove and re-install is by FTP

A simple solution would be to add "delete" button to the "Broken themes" list.

[obenland]

I like the idea! Added an updated patch that simplifies the the markup a bit and also adds a style for tablets/mobile devices to display that table full width.

[ocean90]

It's already possible to delete a broken theme in Multisite, fine with a button here. But it needs a current_user_can( 'delete_themes' ) check.

[ocean90]

In 29924:

Themes: Make it possible to delete broken themes.

props ideag, obenland.
fixes #28165.

[vloo]

#12694 was marked as a duplicate.

[DrewAPicture]

#12694 was marked as a duplicate.