[439237] Enable  all representation creation menu from edges

(Reported on 1.0.x from bug 439140)

Bug: 439237
Change-Id: I53ab38e6a0370fba733cbcb4879a25eedd906522
Signed-off-by: Maxime PORHEL <maxime.porhel@obeo.fr>
Cherry-picked-from: 15d1d19e3de11a97a1a5c7f7aa89a2424d1819b0
[438808] Remove the default editor choice for ecore

This was done to avoid the Sirius Ecore Editor to be the default editor.
This should have been done in its declaring plugin. We do not report the
code in the sample plugin, because the editor is well declared with
default=false.

Bug: 438808
Change-Id: If8b0505eea67b3ae26fc98e65c735f7be9285f13
Signed-off-by: Maxime PORHEL <maxime.porhel@obeo.fr>