Support initializing logger and sinker by configuration

[yyh-graphsql]

I have a few requirements:

• I want to use different logger in the client code, which each logger can sink to different files. (Which now in glog, I think I can only sink to a specific prefix file)
• If it is possible the logging file names xxx.LOG; xxx.LOG.xxx. But not seperated by log level (Actually I want to seperate logging files by the type of logging, e.g. rpc info logging, other statistics logging)?
• Can we have a configuration to set the logger and its sinker. (logger shows what the logging belongs to, sinker shows the destination and the rotate threshold)

Or Are there any possible ways to do things above based on glog?