…ommandMessageHandler` (kbond)

This PR was squashed before being merged into the 6.4 branch.

Discussion
----------

[Console][Messenger] add `RunCommandMessage` and `RunCommandMessageHandler`

| Q             | A
| ------------- | ---
| Branch?       | 6.3
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Tickets       | n/a
| License       | MIT
| Doc PR        | todo

Similar to #49813, when using the scheduler it could be useful to execute commands.

## Usage

```php
use Symfony\Component\Console\Exception\RunCommandFailedException;
use Symfony\Component\Console\Messenger\RunCommandMessage;

try {
    $context = $bus->dispatch(new RunCommandMessage('my:command'));

    $context->output; // string - output of command
    $context->exitCode; // int - the exit code
catch(RunCommandFailedException $e) { // if exit code is non-zero or command threw exception
    $e->context->output; // string - output of command
    $e->context->exitCode; // int - the exit code
    $e->getPrevious(); // null|\Throwable exception command threw if applicable
}

// "never" fail
$context = $bus->dispatch(new RunCommandMessage('my:command', throwOnNonSuccess: false, catchExceptions: true));
```

TODO:
- [x] wire up
- [x] tests

Commits
-------

dd5b0b7 [Console][Messenger] add `RunCommandMessage` and `RunCommandMessageHandler`