[422957] Refactor
CreateRepresentationFromRepresentationCreationDescription

The class CreateRepresentationFromRepresentationCreationDescription of
org.eclipse.sirius.table.ui was deprecated. All common stuffs for the
same action in diagram, table.ui, tree.ui are grouped in
AbstractCreateRepresentationFromRepresentationCreationDescription.
Some methods of ITableCommandFactory and ITreeCommandFactory have been
pull up in ICommandFactory.

Change-Id: I5874f9bd39961ab92d28880c7ec4bffb4f5d681d
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>
[422957] Remove deprecated getAllActivatedEdgeMappings from
DiagramDescription and Layer.

The internal methods getAllActivatedEdgeMappings in ContentHelper are
deprecated and always return an empty list. This is dead code, so the
corresponding elements in meta-model are removed.

Change-Id: I0d5be7364160c315eed2c685f5b4b0b4fc7cf7b2
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>