Refactoring the role management interface (error handling still missing).
Patching notification for workspace subscription.
Merge pull request #685 from ngodfraind/refactoring-roles-tool

Refactoring the role management interface (error handling still missing)...
Merge pull request #686 from ngodfraind/notifications-bugfix

Patching notification for workspace subscription.
Fixing user selection in message form.
Adding success messages.
Error handling for role list.
Merge pull request #689 from ngodfraind/fixing-messagery

Fixing user selection in message form.
Adding initialisation date to the user entity.
typos
Merge pull request #691 from ngodfraind/refactoring-roles-tool

Refactoring roles tool