Add personnal boxes

[jrmi]

Private box are box only for authenticated user.
To add private box we need:

• To create a store wrapper with that API:
  • constructor(store) => keep the store internally for further references
  • getStore(user) => return an object with original store API but box id is rewriten if the box is "private" (we can rewrite box id like that _${userID}_${boxId}) to access transparently to user specific store. boxId starting with _ are internal only.
• Allow to create private store by using the already defined personnal box options
• To use that wrapper everywhere a store is used:
  • In CRUD views
  • In execute middleware context