azure/network: Conform Azure Network Security Groups to Tectonic generic platform standards (#991)

* azure/nsg: Initial commits for Azure NSG creation (#337)

* Revise NSG priority

* azure/nsg: cleanup and make nsg rule creation optional (#7)

* azure/nsgs: add descriptions for external vars & update docs/examples
* azure/nsg: make NSG rule creation optional
* azure/nsg: add external nsg for k8s api & option to create its rules
* azure/nsg: update docs and examples
* azure/nsg: cleanup unused code
* azure/nsg: add default resource_group_name & network_security_group_name
* cleanup gitignore

* azure/nsg: Remove unused vars, format, regenerate examples

* azure/nsg: Configure more secure defaults for Tectonic NSG rules

* azure/nsg: fix conditional & resource_group_name for console NSG

* azure/nsg: Nit fixes

* azure/nsg: Simplify NSG rule logic, better var names, less vars

* azure/nsg: Update NSG rule creations

Setting the creation of all NSG rules to be dependent on the value
of `external_nsg_*`. Remove extraneous vars.

* azure/nsg: Remove `tectonic_azure_create_nsg_rules`

.gitignore

@@ -9,4 +9,4 @@ tectonic-*.tar.gz
 tectonic-license.txt
 terraform.tfstate*
 terraform.tfvars
-/build/
+build/