This change introduces minimum log level support.
GO_DISCOVERY_LOG_LEVEL config can be used to set the log level.
When set, no logs below GO_DISCOVERY_LOG_LEVEL will be printed.
Possible log levels are debug, info, error, fatal.
Log severity sequence is debug < info < error < fatal.
In case of invalid/empty log level, it print all logs.
Fixesgolang/go#40339
Change-Id: I66116e6778eb6386bf1e8df6947078a78fece691
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/245797
Reviewed-by: Julie Qiu <julie@golang.org>
Amarjeet Anand