Include modified version of SlapOS parameter editor and a prototype gadget using react-jsonschema-form

* Case of required properties

* The issue was that when a lot of change management had the same effective date, sometimes, fixing the consistency of the change management led to invalidating the one that was the latest one.
* XXX CLN: Maybe some verification on the version would have been better.

* Also move the variable definition before they are used.

1. add copy&paste excel
2. show message when copy
3. update total when value change

css name