Add confirmation for deleting posts/comments

[MrKaplan-lw]

Requirements

• This is a feature request and not a bug report. Otherwise, please create a new bug report instead.
• Please check to see if this request (or a similar one) already exists.
• It's a single feature. Please don't request multiple features in one issue.

Describe the feature you'd like

The delete button is right next to the edit button, it would help prevent accidental deletions if there was a confirmation prompt before deleting a post or comment.

[dessalines]

I think we have a previous issue for this one, but for restoreable actions, there isn't much reason to do this. If you accidentally click delete on a post / comment, you'll instantly see a restore button.