Implement a selection rotation handle

[ThienDW]

Issue Summary

Currently when selecting and moving an area using the select tool, you can only move and stretch it- being able to rotate by positioning your mouse near the corner would greatly improve the functionality of the tool.

Video or Image Reference

This feature in other similar programs:

[J5lx]

It is already possible to rotate selections in Pencil2D by holding the Ctrl key. I’ll consider this an enhancement request to make it more intuitive by adding a dedicated rotation handle to selections like we do on the camera layer (in nightly builds).