Bevy: Enabling transparency is cumbersome

[cart]

Currently when using common materials like ColorMaterial and StandardMaterial, users need to remember to enable draw.is_transparent. This will be a common "foot gun" and it should really happen automatically if the color has an alpha component.

// currently this is required
world.spawn(NodeComponents {
    material: materials.add(Color::rgba(1.0, 0.9, 0.9, 0.4).into()),
    draw: Draw {
        is_transparent: true,
        ..Default::default()
    },
    ..Default::default()
})

// ideally the `0.4` alpha value results in alpha transparency
world.spawn(NodeComponents {
    material: materials.add(Color::rgba(1.0, 0.9, 0.9, 0.4).into()),
    ..Default::default()
})

[iMplode-nZ]

Yeah I just shot myself in the foot with this.