Update adb-exfiltration-protection to use azurerm v4

[r3stl355]

One of several updates to existing templates to make them compatible with azurerm v4, tracked in https://github.com/databricks/terraform-databricks-examples/issues/144

Changes:

• Add subscription_id parameter: it is mandatory in azurerm v4
• Remove no_public_ip: it is true by default in azurerm v4
• Move the Teraform required module declaration to providers.tf for consistency with other modules
• Reduce output variables, some are part just inputs
• Update README.md
• Make corresponding and similar changes to modules/adb-exfiltration-protection

[alexott]

@r3stl355 I agree about your comment that this is too coarse grained - we have #99 and #88 for relevant parts