Simplify the paper object

Branching, LaTeX specific stuffs should go to their own component. This
applies modularisation to data as for code.
Add role and phase components
Add default settings for roles
Add basic permission entity management
Add more work on entity component system

Roles are now a component that is attached to the paper entity.
Make users and papers entities with components

The core and compiler bundles bring their own data in a modular way.
Users and papers are just entities, with no other meaning than just
existing.

core bundle brings:
 - user basic data (first name, last name, email address, ...),
 - paper basic data (title, last modification),
 - paper roles (authors, reviewers, ...)

compile bundle brings:
 - paper LaTeX compiler settings
Fix test scenarios