[BE] Add Copy to Clipboard Button #1925

Requirements

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

Describe the feature you'd like

I would like to request the addition of a single-click copy to clipboard button in all relevant places. This button would be located in the right top corner of code blocks, quotes, and post/comment sources, and would be represented by a clipboard icon. When clicked, the button would automatically copy the text to the user's clipboard, making it easy to paste the text elsewhere.

Originally posted by 8ullyMaguire in #1925