Make SerilogLogger type public

[victorhurdugaci]

Since the only public type in this package is the extension methods of the logger factory, if you want to create a logger instance, you always have to go through the factory.

For the WebApps logger, we just need an instance of the serilog logger, but that forces us to create an factory before we can create the logger. It would be useful to have that type public so we can instantiate it directly.

[nblumhardt]

Thanks for the feedback Victor, sounds fine. I can make this change in the next day or two, or happy to accept a PR if you can send one.

[merbla]

@nblumhardt we will have to open up SerilogLoggerProvider & SerilogLoggerScope in addition to SerilogLogger.

Not sure if that is the intent.

[nblumhardt]

Released in 1.2.0