[ADD] ability to add note at the top of form when creating a task

[natacha-beck]

Close #1025.

To test if please add (or not) the following on a Boutiques descriptor (in custom section):

        "cbrain:input_notes": [
            "Note 1: this is the first note",
            "Note 2: this is the  note"
        ],

It works for bot Boutiques integrato old and new.

[MontrealSergiy]

works on my local install (new boutiques)