Change default Docker group for nasqueron-dev-docker

Summary:
As we provision a group nasqueron-dev-docker for Docker devserver,
we can use it for Docker too instead of the default docker one.

Security implication: members of the nasqueron-dev-docker group
has now root access on the Docker engines hosts.

Ref T1724

Test Plan:
salt dwellers state.sls roles/paas-docker/docker/config has correctly
provisioned /etc/docker/daemon.json with expected configuration.

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1724

Differential Revision: https://devcentral.nasqueron.org/D2668