Provide Descriptive Error when Enterprise-only Paths Called in Open-source Version

[marcboudreau]

This PR addresses Issue #11539. It expands the entPaths slice of framework.Path pointers, which currently only contains a single path, replication/status, to include all paths for enterprise-only features. This will allow the open-source version of Vault to return a more descriptive error if enterprise Vault CLI commands are sent to it.

All paths related to enterprise-only features will share a common handler that returns a logical.Response that contains the error message enterprise-only feature along with a logical.ErrUnsupportedPath error. From the client perspective, here's the response received from an open-source edition Vault server, using curl:

$ curl -H "X-Vault-Token: $VAULT_TOKEN" -d '{"custom_metadata": {"foo": "abc", "bar": "123"}}' "$VAULT_ADDR/v1/sys/namespaces/ns1"
{"errors":["enterprise-only feature"]}

And using the vault CLI:

$ vault namespace create ns1  
Error creating namespace: Error making API request.

URL: PUT http://localhost:8200/v1/sys/namespaces/ns1
Code: 404. Errors:

* enterprise-only feature

Behaviour Change

This change includes a minor behavioural change to the handling of the existing replication/status path, so that requests sent to it will result in the same response as all of the other paths being introduced. Sending a read operation to this path in the open-source edition, used to result in an HTTP 200 response with the following body:

{
  "data": {
    "mode": "disabled"
  }
}

After this change, this endpoint will behave as described above.

[mpalmi]

Looks really good! I wonder if it'd be worthwhile to add some go tests for this change?

[marcboudreau]

I've refactored the code a bit, so that we can add a test in the enterprise repository that will flag any discrepancies between the results of the entStubPaths and the entPaths functions.

[mpalmi]

Still looks good 😄. I added one nit about the commented-out path, but it is not a blocker.

[mpalmi]

Might be worthwhile to drop this or pull the comment from below up here and note that it will be handled separately below.

[marcboudreau]

I think dropping the comment is better. Without that comment the elements of the slice will all be aligned.