skylog: add job_name, service_name, hostname to LogRecord
skylog: add job_name, service_name, hostname to LogRecord

This makes those fields usable everywhere.

As discussed in comment, no better way to do it.

Also remove few per-msg gethostname() calls.

markokr/skytools,markokr/skytools,tarvip/skytools,overdrive3000/skytools,tarvip/skytools,overdrive3000/skytools,overdrive3000/skytools,tarvip/skytools,markokr/skytools