feat: add Otne icon

[beanflame]

No description provided.

[PKief]

Hi thank you for the icon suggestion :) To keep the icons consistent within this extension I try to avoid gradients and it's important to pick the colors of the Material Design Color palette.

What do you think about removing the gradient and picking a solid color instead, for instance like this:

[beanflame]

嗨，谢谢您的图标建议 :) 为了在此扩展中保持图标一致，我尽量避免渐变，并且选择Material Design Color 调色板的颜色很重要。

您如何看待删除渐变并选择纯色，例如：

well, My icon has been rewritten and updated
@PKief

[PKief]

Thank you very much! Looks good to me :)