[TORQUE-740] Provide a mechanism to inspect torquebox configuration from code

Fixes: https://issues.jboss.org/browse/TORQUE-740

Adds support for queues and topics:

```ruby
TorqueBox::Messaging::Queue.lookup('/queues/something')
TorqueBox::Messaging::Queue.list

TorqueBox::Messaging::Topic.lookup('/topics/something')
TorqueBox::Messaging::Topic.list
```

Added documentation to the code and manual (with examples).