Implement AristotleDataCollector and register it in FeedServe.

Still need to figure out the HDB payload conversion, so will add collectible + that in a future CL.

TESTED:

```
$ stubby call localhost:7777 FeedServe.CollectForPolicyIds 'entity { type: MACHINE name: "oxzz11" metadata { hostname: "oxzz11" }} policy_id: "aristotle-naptime-status"'
entity_response {
  entity {
    type: MACHINE
    metadata {
      hostname: "oxzz11"
    }
    name: "oxzz11"
  }
  feed_payload_map {
    key: "aristotle-naptime-status"
    value {
      aristotle_payload {
        response {
          naptime_requests {
            naptime_request_id: "7165010080226107292"
            machines {
              machine_name: "oxzz11"
              status {
                status: POWER_ON_REQUESTED
              }
            }
            requester: "aristotle-dev"
            request_time {
              seconds: 1756277166
              nanos: 745725549
            }
          }
        }
      }
    }
  }
}
```

PiperOrigin-RevId: 845491191
Change-Id: I4b96a05fe52a0ba27f9da69ae75a3f928b35b1af
1 file changed
tree: b920b995d4269abbaaedcdb8560b96038742adc3
  1. linux/
  2. .gitmodules