Allow cropping an avatar before setting it (#32565)

Provide a cropping tool on the avatar editing page, allowing users to
select the cropping area themselves. This way, users can decide the
displayed area of the image, rather than us deciding for them.

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Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: Giteabot <teabot@gitea.io>

web_src/css/index.css

@@ -40,6 +40,7 @@
 @import "./features/codeeditor.css";
 @import "./features/projects.css";
 @import "./features/tribute.css";
+@import "./features/cropper.css";
 @import "./features/console.css";
 
 @import "./markup/content.css";