Provision DevCentral local configuration

Summary:
This will permit to manage devcentral configuration easily

Ref T2099

Test Plan: salt docker-002 state.sls_id /srv/phabricator/devcentral/conf/local/local.json roles/paas-docker/containers/phabricator

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T2099

Differential Revision: https://devcentral.nasqueron.org/D3623