[KDirOperator] Allow renaming files from the context menu

Summary:
BUG: 189482
FIXED-IN: 5.67

Depends on D17595

Test Plan:

• Using the menu item works to rename one or more items
• The menu item is disables when there's no selection
• This menu item is inappropriately enabled for items that cannot be deleted, just like the trash/delete menu item (pre-existing bug, will fix in another patch)

Reviewers: Frameworks, Dolphin, meven

Reviewed By: meven

Subscribers: meven, cfeck, emateli, elvisangelaccio, markuss, dhaumann, kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D17596