Update LoadBalancer & sub-resources namespace; Change add node behavior; Functionality to remove a node by id

- The namespace change (\OpenCloud\LoadBalancer\Resources\* -> \OpenCloud\LoadBalancer\Resource\*) was made to accommodate the new functionality which will auto-populate sub-resources using the correct sub-resource classes(ex: \OpenCloud\LoadBalancer\Resource\Node vs stdClass).
- Remove LoadBalancer::addNodes() and refactor addNode() to add the node immediately when the function is called. Prior to this change addNode would store the node locally, queueing up each new node until a call to addNodes() was fired. While this is a great idea the underlying implementation left a lot to be desired. While addNode queued up each new node, addNodes did not fire a single API call. Instead it iterated over each node and called Create(). Also, addNodes() only returned the http response for the last call. Since I could not figure out a way to cleanly implement addNodes, and b/c I wanted to check the response for each API call, I removed addNodes().
- Add LoadBalancer::removeNode()