Add optional parameter for unauthenticated metrics access

[vgsantoniazzi]

Description

There's no way to generate unauthenticated metrics access. I've tried to use the merge config files but it seems that the "tcp" listener got overridden by the second file.

Open issue: https://github.com/hashicorp/vault/issues/5860

Documentation

TODOs

Please ensure all of these TODOs are completed before asking for a review.

• [ ] Ensure the branch is named correctly with the issue number. e.g: feature/new-vpc-endpoints-955 or bug/missing-count-param-434.
• [ ] Update the docs.
• [ ] Keep the changes backward compatible where possible.
• [ ] Run the pre-commit checks successfully.
• [ ] Run the relevant tests successfully.
• [ ] Ensure any 3rd party code adheres with our license policy or delete this line if its not applicable.

Related Issues

[hashicorp-cla]

All committers have signed the CLA.

[TomGudman]

Cool! Exactly what were going to do! Thank you!

[rcousens]

Would love to see this merged as it is the last stumbling block in automating our metrics setup for vault!

[vgsantoniazzi]

@rcousens replaced the underscore with hyphens. Does it look good now?

[vgsantoniazzi]

@robmorgan can you take a look?