[IMP] website: allow defining the module used for the xml_id
[IMP] website: allow defining the module used for the xml_id

When a new page is created, we want to allow the definition of the xml_id
as 'website.XXX' in order to have clean url in the frontend and not always
take the same module name than the template module name. Since the page
with url 'page/website.XXX' are parsed by the website controller to be
displayed as 'page/XXX'.
e.g. in studio we create page on the fly and don't want url as:
'www.odoo.com/page/website_studio.XXX'

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo