Add a feature to apply basic shapes to path attachments

[misaki-eymard]

Currently(v4.1.21), path attachments can only be shaped manually, so it is difficult to create a regular circle or square accurately. If you add some buttons to apply basic shapes, it would be more efficient.

Related forum post: https://esotericsoftware.com/forum/d/24207-spine-%E6%98%AF%E5%90%A6%E8%80%83%E8%99%91%E6%B7%BB%E5%8A%A0%E4%B8%80%E4%B8%AA-%E6%9B%B2%E7%BA%BF%E7%9B%B4%E6%8E%A5%E5%9B%BE%E5%BD%A2%E7%BB%98%E5%88%B6

[erikari]

+1 here: https://esotericsoftware.com/forum/d/25510-importing-paths-as-assets