Using the XBlock i18n Service for ORA2

And thusly, we use the i18n Service. 

@wedaly @gradyward 

FYI @sarina we're picking up the i18n service in ORA2.
I would recommend adding translators comments for both "Peer Assessment" and "Self Assessment" phrases. Remember translators may not have technical background and may not have ever seen an ORA component before, so explaining what these terms are conveying/what they mean/how they are used (as appropriate) will help translators a great deal.