[CT-1444] Structured logging: combine node_info events with different logging levels

[gshank]

Prior to this ticket a number of logging events had different event classes depending on the "level" of the logging. This makes it more difficult for consumers of the logs since they would have to subscribe to all versions of the events.

This ticket collapses the multiple events into single events.

This is spun off as part of the work being done in #5663 (CT-1048). Additional work will be done in that ticket to create proto messages for various nodes and node configs.