add support for grpc loggerV2

[bsushmith]

Is your feature request related to a problem? Please describe.
The current salt logger interface doesn't support grpc loggerV2 interface. Due to which in shield, we have multiple loggers at different layers operating instead of one standard logger across.

Describe the solution you'd like
Make salt logger compatible with grpc logger by refactoring the existing salt logger interface. A few of the methods have to be renamed in salt logger to be able to inject into grpc context so that we could use this logger with custom logging rules.