[2.3, HWTv2] Logs still sent with node object

Previously MAAS sent almost all data about a node over the node websocket. This meant loading the node-details page took a large amount of data just to see basic information. With MAAS 2.3 the node-details page only loads the commissioning or testing results as needed speeding up page load time while decreasing the amount of bandwidth needed.

The logs(seen on the logs tab) are still being sent with the node object. Using a VM with no LLDP data found and minimal lshw data requires the following amount of bandwidth and memory.

node.summary_yaml: 37056B
node.summary_xml: 29548B
node.installation_results: 12269B
Total: 79KB

Like commissioning and testing results node log data should only be loaded as needed. Because the summary_yaml and summary_xml are the combination of the lshw and lldp commissioning results using the current node-results websocket isn't possible. A new method should be added to the node websocket, getSummary, which will return the summary in the requested form. This data should only be sent when needed and no longer always sent with the node object.