docs(quickstart): docker is not running

[noelmcloughlin]

Issue/Feature Description:
We need to update quickstart guide to include systemctl start docker step.

On Ubuntu 18.04 the QuickStart Guide procedure fails (in Ansible) at this step:

TASK [auth-installer : install keystone with the docker] *****************************************************************************************************
failed: [localhost] (item=bash ./script/keystone.sh install docker) => {"changed": true, "cmd": "bash ./script/keystone.sh install docker", "delta": "0:01:52.
124831", "end": "2020-10-04 16:24:01.836658", "item": "bash ./script/keystone.sh install docker", "msg": "non-zero return code", "rc": 1, "start": "2020-10-04
 16:22:09.711827", "stderr": "Warning: failed to get default registry endpoint from daemon (Cannot connect to the Docker daemon at unix:///var/run/docker.sock
. Is the docker daemon running?). Using system default: https://index.docker.io/v1/\nCannot connect to the Docker daemon at unix:///var/run/docker.sock. Is th
e docker daemon running?\ndocker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.

This is because installing docker-ce (apt install) did not start Docker.

Why this issue to fixed / feature is needed(give scenarios or use cases):

How to reproduce, in case of a bug:

Following https://docs.sodafoundation.io/soda-gettingstarted/quickstart/ on Ubuntu 18.04

Other Notes / Environment Information: (Please give the env information, log link or any useful information for this issue)

root@ubuntu-bionic:~/installer-v1.1.0/ansible# wget https://download.docker.com/linux/ubuntu/dists/bionic/pool/stable/amd64/docker-ce_18.06.1~ce~3-0~ubuntu_am
d64.deb && dpkg -i docker-ce_18.06.1~ce~3-0~ubuntu_amd64.deb
--2020-10-04 16:38:30--  https://download.docker.com/linux/ubuntu/dists/bionic/pool/stable/amd64/docker-ce_18.06.1~ce~3-0~ubuntu_amd64.deb
Resolving download.docker.com (download.docker.com)... 13.224.67.52, 13.224.67.94, 13.224.67.63, ...
Connecting to download.docker.com (download.docker.com)|13.224.67.52|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 40225142 (38M) [application/x-debian-package]
Saving to: ‘docker-ce_18.06.1~ce~3-0~ubuntu_amd64.deb’

docker-ce_18.06.1~ce~3-0~ubuntu_amd64.d 100%[=============================================================================>]  38.36M   658KB/s    in 63s

2020-10-04 16:39:54 (623 KB/s) - ‘docker-ce_18.06.1~ce~3-0~ubuntu_amd64.deb’ saved [40225142/40225142]

(Reading database ... 107453 files and directories currently installed.)
Preparing to unpack docker-ce_18.06.1~ce~3-0~ubuntu_amd64.deb ...
invoke-rc.d: policy-rc.d denied execution of stop.
Unpacking docker-ce (18.06.1~ce~3-0~ubuntu) over (18.06.1~ce~3-0~ubuntu) ...
Setting up docker-ce (18.06.1~ce~3-0~ubuntu) ...
invoke-rc.d: policy-rc.d denied execution of start.
Processing triggers for ureadahead (0.100.0-21) ...
Processing triggers for systemd (237-3ubuntu10.42) ...
Processing triggers for man-db (2.8.3-2ubuntu0.1) ...

root@ubuntu-bionic:~/installer-v1.1.0/ansible# docker ps
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
root@ubuntu-bionic:~/installer-v1.1.0/ansible# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: https://docs.docker.com
root@ubuntu-bionic:~/installer-v1.1.0/ansible# systemctl start docker

root@ubuntu-bionic:~/installer-v1.1.0/ansible# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
   Active: active (running) since Sun 2020-10-04 16:41:04 UTC; 2s ago
     Docs: https://docs.docker.com
 Main PID: 22781 (dockerd)
    Tasks: 21
   CGroup: /system.slice/docker.service
           ├─22781 /usr/bin/dockerd -H fd://
           └─22807 docker-containerd --config /var/run/docker/containerd/containerd.toml

Oct 04 16:41:03 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:03.235933274Z" level=info msg="ClientConn switching balancer to \"pick_first\"" module=gr
Oct 04 16:41:03 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:03.236251657Z" level=info msg="pickfirstBalancer: HandleSubConnStateChange: 0xc4201bdca0,
Oct 04 16:41:03 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:03.236612026Z" level=info msg="pickfirstBalancer: HandleSubConnStateChange: 0xc4201bdca0,
Oct 04 16:41:03 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:03.236858859Z" level=info msg="Loading containers: start."
Oct 04 16:41:03 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:03.687450150Z" level=info msg="Default bridge (docker0) is assigned with an IP address 17
Oct 04 16:41:03 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:03.898567756Z" level=info msg="Loading containers: done."
Oct 04 16:41:03 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:03.959431031Z" level=info msg="Docker daemon" commit=e68fc7a graphdriver(s)=overlay2 vers
Oct 04 16:41:03 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:03.959643327Z" level=info msg="Daemon has completed initialization"
Oct 04 16:41:04 ubuntu-bionic dockerd[22781]: time="2020-10-04T16:41:04.044909571Z" level=info msg="API listen on /var/run/docker.sock"
Oct 04 16:41:04 ubuntu-bionic systemd[1]: Started Docker Application Container Engine.