[MIG] website_blog: new api migration

- Task: https://www.odoo.com/web?debug=#id=9783&view_type=form&model=project.task&action=333&active_id=131
- Pad: https://pad.odoo.com/p/r.gSXNQBNaLZL5Ausm
Seems correct, defined but not used 
addons/website_blog/controllers/main.py
123:        post_url = QueryURL('', ['blogpost'], tag_id=tag and tag.id or None, date_begin=date_begin, date_end=date_end)
149:            'post_url': post_url,
193:        post_url = QueryURL('', ['blogpost'], blogpost=blog_post, tag_id=tag_id, date_begin=date_begin, date_end=date_end)
224:            'post_url': post_url,