[Feature] Serilog w/ NLog support {WIP}

Support for using serilog piping to NLog

Depends on: https://github.com/serilog/serilog/pull/153
I haven't had a chance to use Serilog yet, however is there a reason we'd want to hardcode Castle Core to using the NLog sink rather than allow the consumer to set their own configuration like the log4net and NLog integration?