support translations on entry.type="page"

[gustabot42]

entry.type="page" are not listed in translation views, there is no way to manage translated page with the same logic of "entry"s, with respect to language menu in templates

[gustabot42]

a deviation is to use a filter in the views definition, with special tag for pages.

'/:slug/': {'view': 'entry', 'if': lambda e: 'page' in e.tags}, '/:year/:slug/': {'views': ['entry', 'draft'], 'if': lambda e: 'page' not in e.tags},