This patch fixes below
* Previously fatalIf() never writes log other than first logging target.
* quiet flag is not honored to show progress messages other than startup messages.
* Removes console package usage for progress messages.
This is an attempt cleanup code and keep the top level config
functions simpler and easy to understand where as move the
notifier related code and logger setter/getter methods as part
of their own struct.
Locks are now held properly not globally by configMutex, but
instead as private variables.
Final fix for #3700
logurs is not helping us to set different log formats (json/text) to
different loggers. Now, we create different logurs instances and call
them in errorIf and fatalIf
* Implements a Peer RPC router that sends info to all Minio servers in the cluster.
* Bucket notifications are propagated to all nodes via this RPC router.
* Bucket listener configuration is persisted to separate object layer
file (`listener.json`) and peer RPCs are used to communicate changes
throughout the cluster.
* When events are generated, RPC calls to send them to other servers
where bucket listeners may be connected is implemented.
* Some bucket notification tests are now disabled as they cannot work in
the new design.
* Minor fix in `funcFromPC` to use `path.Join`
