Added private link option to the exfiltration protection example

[mwojtyczka]

The example currently doesn't have a private link setup included as indicated in the architecture diagram. The PR adds an optional private link along with other changes based on field experience.

Changes:

• Added missing private link setup. Added variable to enabled/disabled the private link. By default disabled since it requires the Databricks Enterprise tier so won't work for all customers.
• Added ready configuration for each region (webapp, SCC relay, hive metastore, control plan). The configuration can still be provided explicitly as before. This greatly simplifies the setup for the customers.
• Updated Readme
• Added output.tf so that users don't have to do it
• Upgraded provider (databricks, aws) versions
• Whitelisted repositories for maven and spark packages
• Updated aws services setup as per the latest aws provider version
• Refactored in places and provided better comments
• Deployment tested with and without private link enabled

[alexott]

Can you resolve conflicts - there was a merge today. I'll review in the meantime

[mwojtyczka]

Can you resolve conflicts - there was a merge today. I'll review in the meantime

resolved now, thank you!