[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

No, sort can't correctly in this case, because here we need sort in reverse order base on length of character.

##### Using <i>sorted()</i> Method (from models.py line 5316)
<pre>(Pdb) words = sorted(words, reverse=True)
(Pdb) words
[(u'odoo', u'Odoo', u'//www.odoo.com', False), (u'new1', u'New1', u'http://new1.com', False), (u'new', u'new', u'//www.new.com', False), (u'Odoo CRM', False, u'https://www.odoo.com/page/crm', False), (u'Odoo CMS', u'Odoo Wesite Builder', u'https://www.odoo.com/page/website-builder', False)]
</pre>

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##### Using <i>sort()</i> Python Method 
Actually we want this result, Reversed long length results.
<pre>words.sort(key=lambda t: len(t[0]), reverse=True)
(Pdb) words
[(u'Odoo CMS', u'Odoo Wesite Builder', u'https://www.odoo.com/page/website-builder', False), (u'Odoo CRM', False, u'https://www.odoo.com/page/crm', False), (u'new1', u'New1', u'http://new1.com', False), (u'odoo', u'Odoo', u'//www.odoo.com', False), (u'new', u'new', u'//www.new.com', False)]
</pre>