Need a "svn rename" action

We currently abstract "svn mv" using the "Svn Cut" and "Paste" actions, just like we abstract "mv" using the "Cut" and "Paste" actions. But in both cases, there is a caveat that you can't paste into the same directory you cut from, so it only lets you move files, not rename. For this reason, we added the "Rename" action. However, there is no equivalent "Svn Rename" action.

This should be added. Don't forget to add the documentation to ivle/webapp/filesystem/browser/help-svn.html.