Add container data

[whitmo]

Not sure if this would be interesting to you all, but figured I would see.

This PR adds information about logs shipped from containers to journald via the docker journald driver.

The output to cloudwatch looks like :

{
...
    "container": {
        "id": "7203ffd33e5f",
        "id_full": "7203ffd33e5f5958509d963c6d9d4604b3fbb54213217679011c68e2ef068059",
        "Name": "k8s_border-dnsmasq.c519f80_border-dnsmasq-172.31.224.5_default_858f5fac233909242a78296b9b53347b_d200cabb"
         "tag": "{some-arbitrary-tag-text}"
}