This PR fixes the Nomad Object Namespace <-> Consul ACL Token relationship
check when using Consul OSS (or Consul ENT without namespace support).
Nomad v1.1.0 introduced a regression where Nomad would fail the validation
when submitting Connect jobs and allow_unauthenticated set to true, with
Consul OSS - because it would do the namespace check against the Consul ACL
token assuming the "default" namespace, which does not work because Consul OSS
does not have namespaces.
Instead of making the bad assumption, expand the namespace check to handle
each special case explicitly.
Fixes#10718
This PR adds e2e tests for Consul Namespaces for Nomad Enterprise
with Consul ACLs enabled.
Needed to add support for Consul ACL tokens with `namespace` and
`namespace_prefix` blocks, which Nomad parses and validates before
tossing the token. These bits will need to be picked back to OSS.
This PR adds the common OSS changes for adding support for Consul Namespaces,
which is going to be a Nomad Enterprise feature. There is no new functionality
provided by this changeset and hopefully no new bugs.
