Investigate client-side toggle between inline and parallel diff views

With Rapid Diffs heavily reliant on server-side rendering comes an issue of switching inline and parallel modes on the client. We've done that previously by doing a client-side re-render of the diffs using the data coming from backend. Since we're sending our diffs as HTML this task becomes a challenge to perform without reloading all the diffs. We should investigate into ways of making this possible using CSS or other ways that don't require sending all the data with the diffs or a full diffs reload.