Add support for SPANPlus

[umzi2]

SPANPlus
I know that you prefer to use architectures that are trained and published. But I will leave it to your discretion. Quite a few people are interested in SpanPlus, they support traiNNer-redux and Neosr. So, I think the models will appear quickly. The repository contains ready-made code for detecting parameters, and there is a license. The architecture is also frozen, and will not change.