Remove the reference to the atala-products repository as it's private and change the documentation content accordingly

[yshyn-iohk]

the identus-docs repository is public, but there is a submodule that refers to the atala-products.
As we don't plan to open-source the repository Atala-products, we need to remove this submodule and change the documentation content accordingly.

[FabioPinheiro]

What is the status of this?
I can't find the submodule atala-products

[yshyn-iohk]

I removed this submodule in this PR
The main reason was the inability to check out the private repo from the input-output org, which has a token issued by the hyper ledger org.

But I need some review and confirmation regarding this action from @milosh86 and @petevielhaber.

[milosh86]

@yshyn-iohk I confirm, feel free to remove any reference to atala-prism-products repo, it is not relevant anymore.