* provider/datadog #9375: Refactor tags to a list instead of a map.
Tags are allowed to be but not restricted to, key value pairs (ie: foo:bar)
but are esssentially strings. This changes allows using, and mixing of tags with
form "foo" and "foo:bar". It also allows using duplicate keys like "foo:bar" and "foo:baz".
* provider/datadog update import test.