ENYO-3257: Add a message count updated thru bindings

Enyo-DCO-1.1-Signed-off-by: Yves Del Medico <yves.del-medico@hp.com>
ENYO-3257: Introduced an enyo.Model name Bootplate.Message

Enyo-DCO-1.1-Signed-off-by: Yves Del Medico <yves.del-medico@hp.com>
ENYO-3257: Create a new Bootplate.Message (enyo.Model) with a creation id to add an new message in the collection

Enyo-DCO-1.1-Signed-off-by: Yves Del Medico <yves.del-medico@hp.com>
ENYO-3257: Add a button to remove the first message

Enyo-DCO-1.1-Signed-off-by: Yves Del Medico <yves.del-medico@hp.com>