Allow to rotate selection

[AndreiCherniaev]

Description
It is not user-friendly to rotate selection: 1) Use Selection Tools; 2) Switch to "Move Selected Pixels"; 3) Hold right mouse button.
How it works in Pinta on video.
I suggest to add draw.io-like-functional. In right top side we can rotate by pictogram.

[cameronwhite]

This is closely related to #585 and the in-progress changes in #1515 to have handles for scaling the selected content. Adding a more visual handle for rotation also would go along nicely with that