This changes adds ACL role creation and deletion to the event
stream. It is exposed as a single topic with two types; the filter
is primarily the role ID but also includes the role name.
While conducting this work it was also discovered that the events
stream has its own ACL resolution logic. This did not account for
ACL tokens which included role links, or tokens with expiry times.
ACL role links are now resolved to their policies and tokens are
checked for expiry correctly.
This fixes a bug in the event stream API where it currently interprets
namespace=* as an actual namespace, not a wildcard. When Nomad parses
incoming requests, it sets namespace to default if not specified, which
means the request namespace will never be an empty string, which is what
the event subscription was checking for. This changes the conditional
logic to check for a wildcard namespace instead of an empty one.
It also updates some event tests to include the default namespace in the
subscription to match current behavior.
Fixes#10903
