Add rotate layout shortcut

[pjhfggij]

Before you make the issue, confirm that

• You are running the master build from GitHub actions
• You have read the FAQ and the usage instructions
• You have searched pull requests and issues and have found none similar to your issue
• This problem comes from a failure in the tiling system and not a missing feature

Describe the bug

I've finally found out how to "rotate layout", but there is no shortcut available to invoke it:

none of these shortcut do anything:

I should have waited one more month to make it a one year anniversary :)

To reproduce

1. try any of these built-in shortcuts
2. nothing happens

Expected behavior

Layout rotates same as after switching the toggle in the first screenshot and confirming new settings

Log output

Jun 02 16:04:53 host3 kwin_wayland[2148]: file:///usr/share/kwin/scripts/polonium/contents/code/main.mjs:2753: TypeError: Value is undefined and could not be converted to an object
Jun 02 16:05:36 host3 kwin_wayland[2148]: file:///usr/share/kwin/scripts/polonium/contents/code/main.mjs:2753: TypeError: Value is undefined and could not be converted to an object

[zeroxoneafour]

None of those shortcuts are from polonium, more than likely they are from Bismuth. Polonium shortcuts fall under the KWin category and are all prefixed with Polonium. Also, it appears the shortcut does not exist in the first place. I'll get around to it someday maybe.

[pjhfggij]

Oh I see, that makes sense. Sure, a shortcut would be nice - yes, bismuth had it and I've used it all the time.