[8.0] Port the module 'account_move_template' to the new API

This PR contains the module ***account_move_template*** ported to the new API.
Test and installation seems to me ok.

Let's see what will be the TravisCI response and your reviews :wink: 
I would say yes (but anyway if you do `self.template_line_ids` and the recordset has several records it will raise the same error)