logger: Make output to syslog nicer

logger: Make output to syslog nicer

Resolve the level string in msgWithTime.  This means that the log
level string is included in logs to files and stdout even if syslog
output is enabled.

Resolve the program name using RunMode and BuildInfo, distinguishing
between client, core, and monolithic.

[Backported from 0.14/git-master]