add tenant id to data model

[t0ffel]

think and then somehow add tenant id to the data model

cc @portante

[richm]

For the oVirt use case - oVirt will install common logging (openshift). The logging administrator will login to the openshift console and create a project/namespace for this particular instance of oVirt e.g. ovirt-dev. Logs coming from the ovirt-dev instance will be associated with the ovirt-dev namespace in openshift. They will get placed into indices of the form project.ovirt-dev.$ovirt-dev-uuid.$date where $ovirt-dev-uuid is the openshift namespace uuid of ovirt-dev, as looked up by the k8s metadata filter plugin. So common logging does need some way to associate the namespace name with logs coming from that tenant. @nhosoi is working on this from the common logging/fluentd/mux side.