Bring reproducible builds tutorial up to date

[andreibancioiu]

Description of the pull request (what is new / what has changed)

Fixed links towards examples repository, re-did tutorial on devnet etc.

We've deprecated https://github.com/multiversx/mx-deprecated-reproducible-contract-build-example-sc in favor of https://github.com/multiversx/mx-contracts-rs.

Did you test the changes locally ?

• [x] yes
• [ ] no

Which category (categories) does this pull request belong to?

• [ ] document new feature
• [x] update documentation that is not relevant anymore
• [x] add examples or more information about a component
• [ ] fix grammar issues
• [ ] other