Add shortcut to copy file content hash link

What does this MR do?

• Allows for multiple shortcut handlers to be initialised
• Adds y shortcut to file pages to copy permalink URL.

Are there points in the code the reviewer needs to double check?

Ney.

Why was this MR needed?

UX

What are the relevant issue numbers?

Closes #14470 (closed).

Screenshots (if relevant)