Add Terrafrom MSK PrivateLink example

[bobbyiliev]

Adding a demo example on how to use the Terraform MSK PrivateLink module along with the Materialize Terraform Provider to show how you could automate the Materialize side of the configuration.

Open to suggestions if we should actually extend the module and include the Materialize provider in there directly as well!

[alex-hunt-materialize]

I'd love to see both working together. I imagine that if a customer is already using Terraform for one part of this, they are much more likely to want to use Terraform for both.

You might want that in a separate demo, though. It might be a lot of information all at once.