Rudder

In the ticket #10578, we corrected the fact that is was impossible the add/remove property or change policy mode when the change request message was mandatory by setting a default message for such changes. This doesn't let the possibility to the user to explain why he did the change, and so deflect the interest of having a change message (like having a commit message for a source code modification stating "source modified").

We need to let the user be able to input the message in all cases, and making it UX friendly for properties.

It may be an rather big change, so certainly need to be validated (both the target version and what UX we want to use). It seems that 4.1 is a better target for that than 4.0, even if policy mode is a 4.0 thing (we can live with only default message for it, I believe).