Also they bypass the 'single stdout' restriction

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
<!--- Write the short name of the module, plugin, task or feature below, use your best guess if unsure -->
collections

##### ANSIBLE VERSION
<!--- Paste verbatim output from "ansible --version" between quotes -->
```paste below
2.8, 2.9
```

##### CONFIGURATION
<!--- Paste verbatim output from "ansible-config dump --only-changed" between quotes -->
```paste below

```

##### OS / ENVIRONMENT
<!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. -->
any

##### STEPS TO REPRODUCE
<!--- Describe exactly how to reproduce the problem, using a minimal test-case -->
put callback into collection and whitelist
<!--- Paste example playbooks or commands between quotes below -->
```yaml

```

<!--- HINT: You can paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- Describe what you expected to happen when running the steps above -->
callback works

##### ACTUAL RESULTS
<!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) -->
callback options are ignored
<!--- Paste verbatim command output between quotes -->
```paste below

```

if path:
                    module_loader.add_directory(path)
        
        self._terminated = False
        
        self._failed_hosts = dict()
        self._unreachable_hosts = dict()
        try:
            self._final_q = FinalQueue()
        except OSError as e:
            raise AnsibleError("Unable to use multiprocessing, this is normally caused by lack of access to /dev/shm: %s" % to_native(e))
        self._callback_lock = threading.Lock()
        
        
        self._connection_lockfile = tempfile.TemporaryFile()
    def _initialize_processes(self, num):
        self._workers = []
        for i in range(num):
            self._workers.append(None)
    def load_callbacks(self):
        '''
        Loads all available callbacks, with the exception of those which
        utilize the CALLBACK_TYPE option. When CALLBACK_TYPE is set to 'stdout',
        only one such callback plugin will be loaded.
        '''
        if self._callbacks_loaded:
            return
        stdout_callback_loaded = False
        if self._stdout_callback is None:
            self._stdout_callback = C.DEFAULT_STDOUT_CALLBACK