Move Infinispan Simple tutorials docs to the simple tutorials repository

And integrate it in this build from there

https://github.com/infinispan/infinispan-simple-tutorials/pull/82

Start by reviewing the linked pull request at infinispan/infinispan-simple-tutorials#82 and the build configuration in infinispan.github.io. Determine which Simple tutorial documentation is being moved and how this site should consume it; done means the tutorials live in the simple tutorials repository and are integrated into this site's build.

Written by the indexing model from the issue text.