ENYO-3792: remove Preview icon button

Related JIRA: https://enyojs.atlassian.net/browse/ENYO-3792

"Project" menu has been already moved within Harmonia panel (https://enyojs.atlassian.net/browse/ENYO-2938: #773 )

* ENYO-3792: remove Preview icon button. Project action (Edit/Preview/builds/Debug/Run...) are now available from Harmonia's toolbar withi menu "Project"

Enyo-DCO-1.1-Signed-off-by: Vincent HERILIER vincent.herilier@hp.com