Remember unsaved wiki changes using autosave.js

Open username-removed-52628 requested to merge AbbasFaisal/gitlab-ce:remember-wiki-edits into master

What does this MR do?

Save unsaved edits in a wiki page in browser's local storage using autosave.js.

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

Why was this MR needed?

Screenshots (if relevant)


Does this MR meet the acceptance criteria?

What are the relevant issue numbers?

#24738 (moved)