[ADD] website_forum_seo: add new module for improve forum que/ans description


<b>Task:</b> https://www.odoo.com/web#id=9107&view_type=form&model=project.task&menu_id=3942&action=327
<b>Pad:</b> https://pad.odoo.com/p/r.aAXbFLdZvu62soZi


<b>New Module:</b> website_forum_seo
<b>VIew Demo:</b> https://www.youtube.com/watch?v=_lYH_GrRqso

Hello @tde-banana-odoo ,
  As per your suggestion I try to call <code>@api.onchange('content')</code> but it's didn't give a response to me. 
I'm not sure but I find a reason <code>@api.onchange('content')</code> call only in backend addons form view whose have field (eg. <code>&lt;field name="content"/&gt;</code> ). 

And our case onchange apply to website side forum, textarea field. How to I do onchage on <b>qweb &lt;textarea&gt; field</b> to call onchange? Need suggestion, Thanks