Initial commit for a multi-tenant configuration

This PR adds (basic / Cloud Foundry specific) multi-tenant support.  

Specifically:

1. A new ingestor port can be defined for each CF org/space ([`cf.tenants` manifest setting](https://github.com/logsearch/logsearch-boshrelease/pull/77/files#diff-4ae895efb1f961b6fe8fa8807f404d07R49))
2. The ingestor forwards logs to a [tenant specific queue](https://github.com/logsearch/logsearch-boshrelease/pull/77/files#diff-16adfeea7c6ab604aa7c99f7365bb942R76)
3. The log_parsers pull off each tenant specific queue, and parse using standard filters, and then forward to a tenant specific elasticsearch index - [`index => "logstash-%{tenant}-%{+YYYY.MM.dd}"`](https://github.com/logsearch/logsearch-boshrelease/pull/77/files#diff-71406092a7ed9f19647f893d34cc6892R29)
4. The log parsers include set of (manually configured) [CF Application GUID to Tenant Mappings](https://github.com/logsearch/logsearch-boshrelease/pull/77/files#diff-aae6cc83e85bc7ba404288312173f3e2R2)
5. A set of [standard kibana dashboards is added to the kibana embedded in elasticsearch](https://github.com/logsearch/logsearch-boshrelease/pull/77/files#diff-2de0d04be3cc14378e96040b44546d3cR10)
6.  When the elasticsearch job starts, it [creates a set of dashboards for each configured tenant](https://github.com/logsearch/logsearch-boshrelease/pull/77/files#diff-df08e431dda0ea301e3e3081a57ec33dR27)
7.  The [syslog_drains BOSH errand](https://github.com/logsearch/logsearch-boshrelease/pull/77/files#diff-61b8448ee67c5c838b3bc4859a6d8328R2) can be used to add a set of CF syslog drains for the configured `cf.tenants`
8.  A set of vsphere deployment manifest samples are included
Can you put this `add_field` inside a conditional, only doing it if `tenants` is configured?