bmcweb logging

[Ratan Gupta]

Hi Ed,

I was having issues in getting the logs from bmcweb repo, If I don't 
define the compiler flag(BMCWEB_ENABLE_LOGGING) then it doesn't get me 
any logs in journal(not even error log) and if I define the compiler 
flag then it gets too much debug info.

Seems it happens because we have hardcoded the logelevel  and there is 
no way through which we can change except making the change manually in 
the following place.

https://github.com/openbmc/bmcweb/blob/master/http/logging.hpp#L93

Suggestion is we can define another compile time flag for log level and 
use that log level at the above line for type of logging , by default 
logging should be enabled with error log level.

If there is a need user can play with new compiler flag for more verbose 
logging.

Am I missing something in usage of logging infra?

Ratan