Created by: yurakuratov
- add support of HuggingFace datasets to DeepPavlov
- fixes https://github.com/deepmipt/DeepPavlov/issues/1312
- add configuration files for GLUE dataset tasks
- TorchBertClassifierModel supports regression task when n_classes set to 1 (e.g., glue_stsb)
- add correlation metrics (for GLUE dataset)
- add table with results on GLUE to classifiers doc page