README: Add text from former COPYRIGHT and add links

Format also the text, so it looks nicer on GitHub.

Signed-off-by: Stefan Weil <[email protected]>

Author: stweil

README.md

@@ -1,2 +1,7 @@
-# tessdata_best
-Best (most accurate) trained LSTM models.
+# tessdata_best – Best (most accurate) trained models
+
+This repository contains language data for the
+[Tesseract Open Source OCR Engine](https://github.com/tesseract-ocr/tesseract).
+
+All data in the repository are licensed under the
+Apache-2.0 License, see file [COPYING](COPYING).