Add license and WER information to models description

[gazay]

I've downloaded all models and checked where they come from and if they have a License file inside. I've added a new column to the model URLs table with license information. I've also added a few notes on model performance when I could find metrics in the models' Readme files.

Here is what I found, just to be sure that everything right:

• All alphacephei models released under Apache 2.0
• All Kaldi models (and repackages) released under Apache 2.0
• All daanzu's (https://github.com/daanzu/kaldi-active-grammar/blob/master/docs/models.md) models - AGPL
• French zamia-speeech's (https://github.com/pguyot/zamia-speech/releases) models - CC-BY-NC-SA 4.0
• German zamia-speech model - LGPL-3.0

[nshmyrev]

Thank you!