Add model cards for DeepPavlov models (#3138)

* add empty model cards for every current DeepPavlov model

* fix: replace cyrillic `с` with `c`

* docs: add model cards for current DeepPavlov BERT models

* docs: add links for arXiv preprints

model_cards/DeepPavlov/rubert-base-cased-conversational/README.md

@@ -0,0 +1,18 @@
+---
+language:
+- russian
+---
+
+# rubert-base-cased-conversational
+
+Conversational RuBERT \(Russian, cased, 12-layer, 768-hidden, 12-heads, 180M parameters\) was trained
+on OpenSubtitles\[1\], [Dirty](https://d3.ru/), [Pikabu](https://pikabu.ru/),
+and a Social Media segment of Taiga corpus\[2\]. We assembled a new vocabulary for Conversational RuBERT model
+on this data and initialized the model with [RuBERT](../rubert-base-cased).
+
+
+\[1\]: P. Lison and J. Tiedemann, 2016, OpenSubtitles2016: Extracting Large Parallel Corpora from Movie and TV Subtitles.
+In Proceedings of the 10th International Conference on Language Resources and Evaluation \(LREC 2016\)
+
+\[2\]: Shavrina T., Shapovalova O. \(2017\) TO THE METHODOLOGY OF CORPUS CONSTRUCTION FOR MACHINE LEARNING:
+«TAIGA» SYNTAX TREE CORPUS AND PARSER. in proc. of “CORPORA2017”, international conference , Saint-Petersbourg, 2017.