remove URI components from metadata host service endpoint when generating .mlzconfig

[glennmusa]

Description

Today, users in air-gapped clouds have issues initializing terraform backends when using the full ARM Metadata Host Service Endpoint URI (e.g. "https://management.azure.com/") and instead require just the host name (e.g. "management.azure.com")

This change, when using the deploy.sh quickstart, removes the URI components from the result of az cloud show --query endpoints.resourceManager when the .mlzconfig file is generated so that just the hostname value is passed as a metadata_host argument during terraform backend initialization. See #241 for more information.

Before, a .mlzconfig generated from deploy.sh used to generate a key value pair like this:

mlz_metadatahost=https://management.azure.com/

Now, it should generate a value like this:

mlz_metadatahost=management.azure.com

...and that plays nicer across clouds and azurerm providers.

You can test this manually with the generate_config_file.sh script:

my_tenant_id=$(az account show --query tenantId --output tsv)
my_sub_id=$(az account show --query id --output tsv)
src/scripts/config/generate_config_file.sh -f mytest.mlzconfig -e public -z mytestenvname -l eastus -s $my_sub_id -t $my_tenant_id

Issue reference

The issue this PR will close: #241

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

[glennmusa]

Awaiting on confirmation of expected metadata host values before merging.

[Phydeauxman]

Looks great Glenn, thanks for the quick turn on this...and thanks for providing the quick test. I ran the test and got the expected outcome.

[Phydeauxman]

Looks great Glenn. Took me a little bit to follow your logic here but only because I have never used some of the techniques you are using.