LoggingTriggerHistoryPlugin and LoggingJobHistoryPlugin should use StructuredLogging

[michaelmairegger]

Currently the log is written as string. For better logging those plugins should use structured loggings.

Additionally to that every call to Log.XXX should use structured logging.

[jafin]

I started to take a look at this, once structured logging is introduced, I think it makes less sense to provide ability to configure your own log template message, which the current plugin does. As the order of the parameters, not the placeholder index takes effect. I'll put up a PR for review, and see if this is acceptable.