Feature Request - Custom Setting Support for vnet peerings

[matt-FFFFFF]

Overview/Summary

Adds advanced block support for custom vnet peering naming.

This PR fixes/adds/changes/removes

1. Fixes Feature Request - Custom Setting Support for vnet peerings #397
2. Fixes Module does not create outbound peerings unless dns.enabled = true #403

Breaking Changes

n/a

Testing Evidence

=== RUN   TestConnectivityAdvancedVnetPeeringNameNotSet
TestConnectivityAdvancedVnetPeeringNameNotSet 2022-06-15T00:18:12+01:00 /Users/matt/code/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName/retry.go:91: terraform [init -upgrade=false]
TestConnectivityAdvancedVnetPeeringNameNotSet 2022-06-15T00:18:14+01:00 /Users/matt/code/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName/retry.go:91: terraform [plan -input=false -lock=false -no-color -lock=false -out=./tfplan --parallelism=20]
TestConnectivityAdvancedVnetPeeringNameNotSet 2022-06-15T00:18:27+01:00 /Users/matt/code/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName/retry.go:91: terraform [show -no-color -json ./tfplan]
    /Users/matt/code/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName/advancedVnetPeeringName_test.go:47: Peering name: 'peering-134dd88d-86f2-5006-9401-698a1f46852e' is correct in plan
--- PASS: TestConnectivityAdvancedVnetPeeringNameNotSet (14.68s)
=== RUN   TestConnectivityAdvancedVnetPeeringNameSet
TestConnectivityAdvancedVnetPeeringNameSet 2022-06-15T00:18:27+01:00 /Users/matt/code/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName/retry.go:91: terraform [init -upgrade=false]
TestConnectivityAdvancedVnetPeeringNameSet 2022-06-15T00:18:28+01:00 /Users/matt/code/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName/retry.go:91: terraform [plan -input=false -lock=false -var test_advanced_name=true -no-color -lock=false -out=./tfplan --parallelism=20]
TestConnectivityAdvancedVnetPeeringNameSet 2022-06-15T00:18:40+01:00 /Users/matt/code/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName/retry.go:91: terraform [show -no-color -json ./tfplan]
    /Users/matt/code/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName/advancedVnetPeeringName_test.go:47: Peering name: 'test' is correct in plan
--- PASS: TestConnectivityAdvancedVnetPeeringNameSet (13.16s)
PASS
ok      github.com/Azure/terraform-azurerm-caf-enterprise-scale/tests/terratest/connectivity/advancedVnetPeeringName    28.013s


> Test run finished at 15/06/2022, 00:18:40 <

As part of this Pull Request I have

• Checked for duplicate Pull Requests
• Associated it with relevant issues, for tracking and closure.
• Ensured my code/branch is up-to-date with the latest changes in the main branch
• Performed testing and provided evidence.
• Updated relevant and associated documentation.
• Updated the "What's New?" wiki page (located in the Enterprise-Scale repo in the directory: /docs/wiki/whats-new.md)

[krowlandson]

Evidence for commit e549049 from local run (not committed to repo):

Added hub from secondary location to hub from primary in the test framework, and set enable_outbound_virtual_network_peering = true:

Generated a Terraform plan, which contains the peering with standard naming:

Added the following to the advanced block of the connectivity settings:

Generated a Terraform plan, which contains the peering with custom naming:

[matt-FFFFFF]

/azp run unit

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[krowlandson]

LGTM