Pytorch-ie

* fix and improve `token_based_document_to_text_based()` (335) ArneBinder
* remove cuda from dependencies (330) ArneBinder

:rocket: Features

* add document converters (332) ArneBinder
* implement `token_based_document_to_text_based()` (334) ArneBinder

* upgrade github workflow constraints (327) ArneBinder

:rocket: Features

* add model and taskmodule Interface classes (328) ArneBinder

* set minimum transformers version (325) ArneBinder
* update `datasets` and `transformers` (323) ArneBinder
* Update `pytorch-lightning` (322) ArneBinder
* update (dev) dependencies (321) ArneBinder

:beetle: Fixes

* set minimum `datasets` version (324) ArneBinder

* integrate eval_counts_for_layer() into F1Metric.calculate_counts() (318) ArneBinder

:rocket: Features

* tokenize_document: set text_pair if text is already provided (317) ArneBinder
* conversion of text based document to token based and tokenize document (315) ArneBinder

:beetle: Fixes

* fix statistic value aggregation for empty result lists (316) ArneBinder

:rocket: Features

* aggregate the result of DocumentStatistic (313) ArneBinder
* implement DocumentStatistics (312) ArneBinder