ENGINE-552: As an API user I can write log message from within a reactor script, and retrieve them using an API endpoint.

- missing tests and smoke testing
ENGINE-552: As an API user I can write log message from within a reactor script, and retrieve them using an API endpoint.

- moved LogEntry to internal resource model
Merge branch 'ENGINE-552'
Merge branch 'master' of github.com:evrythng/evrythng-java-sdk