Validate all Azure examples/modules for compatibility with azurerm 4.0

[alexott]

I.e., this could affect us:

• https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/guides/4.0-upgrade-guide#specifying-subscription-id-is-now-mandatory
• https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/guides/4.0-upgrade-guide#azurerm_databricks_workspace_customer_managed_key
• https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/guides/4.0-upgrade-guide#azurerm_databricks_workspace

[r3stl355]

Hey @alexott, I can take this

[r3stl355]

List of examples to convert:

• [x] adb-exfiltration-protection
• [ ] adb-external-hive-metastore
• [ ] adb-kafka
• [ ] adb-lakehouse
• [ ] adb-overwatch
• [ ] adb-private-links
• [ ] adb-squid-proxy
• [ ] adb-teradata
• [ ] adb-uc
• [ ] adb-unity-catalog-basic-demo
• [x] adb-vnet-injection
• [ ] adb-with-private-link-standard
• [ ] adb-with-private-link-exfiltration-protection

As part of this exercise I suggest also updating the READMEs and aligning all the templates to use the same conventions, e.g. providers.tf instead of mix of versions.tf and providers.tf