pages: fixed cached data when `url_cache` is used: `request.template_data` and `request.data` where cached using a shallow copy, causing trouble when a mutable object was used. This has been fixed by using a deepcopy, which should not be a resource issue as `request.data` and `request.template_data` should contain a few data in most cases.

User-agent: *
Allow: /blog/
Allow: /u/
Allow: /b/
Disallow: /libervia.html
Disallow: /mr
Disallow: /login

User-agent: Mediapartners-*
Disallow: /