Refactor DB schemas & Refactor Roles

Put default roles in roles.yaml configuration file
Add section for custom roles in roles.yaml configuration file
Get default role in AclBundle ParseRoleStructures from configuration
file

Create a schemas folder with MySQL and Mongo folder inside
Remove /configuration/users.sql
Separate db schema and data seed in separate files, for each driver
Add users.json in Mongo folder to initialize Mongo DB admin user