add defaultLoggerName to Client

[ksophocleous]

add the ability to set a DefaultLoggerName on the raven client. This default logger name is then set on the packet before Init (but only in case the packet has no Logger name set already)

If the DefaultLoggerName is empty (default), there's no change from the current behaviour.

useful for services that don't want to use the package name as the logger name, it makes more sense to set this once and forget about it.

[mattrobenolt]

Can we expose this as a method to set it? SetDefaultLoggerName(name string) instead. I'm trying to limit the amount of public properties on the Client as possible. Just to avoid things that require locks, etc, and encapsulate this into methods consistently.

[ksophocleous]

yeah good idea, especially since during the read, the client.mu is locked

[ksophocleous]

I will close this pull request in favor of #133