[ADD] added rating, rating_project and rating_project_issue module

 - Task : https://www.odoo.com/web#id=8060&view_type=form&model=project.task
 - Pad : https://pad.odoo.com/p/r.2BmKqyvcwKbiXPRI

[IMP] Added option to install rating module under Project

[IMP] added template to display when customer rates the task/issue

[IMP] Improved template and code

[IMP] : rating , rating_project and rating_project_issue as per new api

[IMP]: rating template

[FIX] : test case failed

[IMP] : code
This method is not generic, the signature should look like 
 `def send_request(self, tempalte_id, template_res_id, partner_id, user_id) ` where
template_res_id is the stage_id.id

because, all the model that will inherit from this mixin won't have a stage_id, partner_id or user_id fields.