[FIX] wesite_slides: use embed for document and presentation
[FIX] wesite_slides: use embed for document and presentation

For performance, we could use iframe with embed document.
But it's more styled to use our own slide design that an iframe
with a long scrollbar.

dfang/odoo,hip-odoo/odoo,Elico-Corp/odoo_OCB,stephen144/odoo,ygol/odoo,stephen144/odoo,ygol/odoo,ygol/odoo,hip-odoo/odoo,microcom/odoo,sysadminmatmoz/OCB,sysadminmatmoz/OCB,hip-odoo/odoo,bplancher/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,sysadminmatmoz/OCB,storm-computers/odoo,stephen144/odoo,microcom/odoo,Elico-Corp/odoo_OCB,microcom/odoo,laslabs/odoo,laslabs/odoo,microcom/odoo,dfang/odoo,laslabs/odoo,ygol/odoo,laslabs/odoo,stephen144/odoo,bplancher/odoo,Elico-Corp/odoo_OCB,bplancher/odoo,ygol/odoo,storm-computers/odoo,bplancher/odoo,dfang/odoo,storm-computers/odoo,laslabs/odoo,bplancher/odoo,microcom/odoo,microcom/odoo,sysadminmatmoz/OCB,storm-computers/odoo,storm-computers/odoo,stephen144/odoo,storm-computers/odoo,Elico-Corp/odoo_OCB,sysadminmatmoz/OCB,sysadminmatmoz/OCB,hip-odoo/odoo,bplancher/odoo,laslabs/odoo,Elico-Corp/odoo_OCB,hip-odoo/odoo,dfang/odoo,sysadminmatmoz/OCB,ygol/odoo,ygol/odoo,stephen144/odoo,Elico-Corp/odoo_OCB