validate input for Azure Region and Terraform Environment on deploy.sh and setup_ezdeploy.sh

[glennmusa]

Description

Today, deploy.sh and setup_ezdeploy.sh use AzureCloud-specific defaults to make it simpler for end-users to deploy. However, they A) may not know these defaults are set for them and B) these defaults may not be valid for the cloud they're deploying to.

This change:

• catches errors where Terraform will fail at execution time for a azurerm environment + Cloud mismatch (e.g. providing "public" with cloud set to "AzureUsGovernment")
• catches errors where MLZ Configuration will fail to provision because the specified Azure region is not valid for the contextual cloud executing the commands (e.g. providing "eastus" with cloud set to "AzureUsGovernment")
• informs the user that defaults are being set for them and provides hints on how to override them

For example, if I set my cloud to AzureUsGovernment:

az cloud set -n AzureUsGovernment

and try to deploy using ./deploy.sh with the defaults, I'll get back these messages and this error:

~/dev/missionlz$ src/deploy.sh -s {my_omitted_subscription_id}
INFO: using the default value 'eastus' for '--location', specify the '--location' argument to provide a different value.
INFO: using the default value 'public' for '--tf-environment', specify the '--tf-environment' argument to provide a different value.
INFO: using the default value 'mlz1619186307' for '--mlz-env-name', specify the '--mlz-env-name' argument to provide a different value.
INFO: setting current subscription to {my_omitted_subscription_id}...
ERROR: could not find region 'eastus' for subscription of '{my_omitted_subscription_id}' in current cloud 'AzureUSGovernment'
INFO: is this a valid region? Try 'az account list-locations' to see what regions are available to you.
INFO: do you have the correct cloud set? Try 'az cloud set' to set it.

and if I provide a valid location, but do not provide a matching terraform environment:

~/dev/missionlz$ src/deploy.sh -s {my_omitted_subscription_id} -l usgovvirginia
INFO: using the default value 'public' for '--tf-environment', specify the '--tf-environment' argument to provide a different value.
INFO: using the default value 'mlz1619186398' for '--mlz-env-name', specify the '--mlz-env-name' argument to provide a different value.
INFO: setting current subscription to {my_omitted_subscription_id}...
ERROR: Terraform environment 'public' is not a valid environment for cloud 'AzureUSGovernment'
INFO: check the valid settings for Terraform environment here: https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs#environment

Issue reference

The issue this PR will close: #172, #173

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles or validates correctly
• BASH scripts have been validated using shellcheck
• All tests pass (manual and automated)
• The documentation is updated to cover any new or changed features
• Markdown files have been linted using the recommended linter. (See .vscode/extensions.json.)
• Relevant issues are linked to this PR

[sstjean]

Code looks solid.

Successfully tested functionality against Commercial and Gov.