Implement new vector cursor for sway

[HalanoSiblee]

Why sway still using xcursor it's almost 2025 Other DE & WM 's started the adoption for vector based cursors I would be glad if this got added into sway and could be easily configured with Boolean options to force or not force the cursor to draw over clients like GTK for example.

svg cursors should be snappy small in size and scalable.

[emersion]

There's no spec for SVG cursors yet. KDE just merged experimental support for these a few days ago.

I do agree that SVG cursors would be better, and I'm following progress on the KDE spec closely.