[FIX] website: optimize SEO in other languages than the default one

When connected as a website manager,
in another language than the default
website language,
it was not possible to use the optimize
SEO feature, because it needed
variables that were not available if the website
was considered as translatable only,
not editable. This is the case
when you are in any other language
than the default website language,
`editable` is `False`
and
`translable` is `True`.

This is a change of behavior compared to Odoo 8.0,
where `editable` was considered to `True`
even if you were only editing the website translations.

opw-668632

addons/website/views/website_templates.xml

@@ -84,12 +84,12 @@
 
 <template id="layout" name="Main layout">&lt;!DOCTYPE html&gt;
     <html t-att-lang="lang and lang.replace('_', '-')"
-          t-att-data-website-id="website.id if editable and website else None"
+          t-att-data-website-id="website.id if (editable or translatable) and website else None"
           t-att-data-editable="'1' if editable else None"
           t-att-data-translatable="'1' if translatable else None"
           t-att-data-edit_translations="'1' if edit_translations else None"
           t-att-data-view-xmlid="xmlid if editable or translatable else None"
-          t-att-data-main-object="repr(main_object) if editable else None"
+          t-att-data-main-object="repr(main_object) if editable or translatable else None"
           t-att-data-oe-company-name="res_company.name">
         <head>
             <meta charset="utf-8" />