Make IGFS metrics available for user

Now in Ignite the only way to see IGFS metrics is to get them programmically from the code. But customers need them to understand what is cached in IGFS, so to expose the metrics would be useful.
There are options to expose the metrics via
1) MBean
2) console Visor .
3) web console ( https://apacheignite-tools.readme.io/docs/ignite-web-console )