Add a link to xnd notebooks (binder)

[xmnlab]

• the link could be called Tutorial Notebooks ...
• create initial page using Pearu's notes
• add table of contents

[acu192]

Possibly fixed by xnd-project/website#9

[xmnlab]

Thanks @acu192 ! awesome!

could you create some notebook with a Table of Content to link to other notebooks? maybe would be good to have some introductory text there. You can use something from Pearu's note [1]

[1] https://xnd.readthedocs.io/en/latest/xndtools/notes/notes1.html