Determine cookbook location

[lenkis]

Currently our cookbook is split over 2 locations:

https://www.tarantool.io/en/doc/2.2/book/app_server/cookbook/

https://github.com/tarantool/examples/tree/master/cookbook

We need to bring the cookbook to a single place -- or rather explicitly differentiate the two locations and interlink them.

[lenkis]

A smart workaround would be to keep all cookbook snippets in tarantool/examples (as the master copy) and to automatically include them into the manual (and to update on the manual's side every time we build the site-end manual).