Rudder

We want to be able to specify in a Technique metadata that a version is deprecated with a message.

A Directive based on a deprecated Technique version get:

- a notification symbol on the directives tree + a tooltip with generic message (like "This directive is based on a deprecated version of the technique") and the deprecation message
- the same thing in the directive tree of a rule
- a notification message in the directive (generic message + deprecation message)