First pass to adding analytics tiers in ec-metal

WIP: Not ready to merge yet

To do:

1) test tiered, standalone config in ec-metal.
2) modify the examples as per config assumptions for analytics

@irvingpop - thanks, I will check how attributes can be nicely passed, right now I have this hack where I read the config file again in private-chef attributes, but that is different from what we do for private-chef.