NT drafting support #878
Description
In order to support the new NT drafting features in Scripture Forge, Serval needs to primary features: chapter-level filtering for training/inferencing and model confidence scores. Serval should already mostly support chapter-level filtering. There is a known issue that needs to be fixed for it to work properly with the way that Scripture Forge configures engines. Serval will also need to be able to return the model confidence score for a pretranslation. The confidence scores will be used to compute a usability score for display to users. An implementation of this algorithm will be provided in the Machine library, so that it can be shared across silnlp and Scripture Forge.