* Add path to `TranslatedContent`

This makes it possible to retrieve the translated page through the `get_page` function.

* Use TranslatedContent::path field in test_site_i18n

Use it with the `get_page` function to get a reference to the page object.

* Let toc is visable through Page & Section variables in templates

* Removed the current toc variable from page & section

Closes #733