Create objects detail pages

[tsmbland]

If you navigate to an object in the admin page you'll see a VIEW ON SITE button in the top-right. Clicking this button gives Server Error (500). Running locally you get, for example Reverse for 'country_detail' not found. 'country_detail' is not a valid view function or pattern name. We should fix this button, or remove it.

Seems like a problem with the get_absolute_url method for the models

This includes adding the relevant view pages (list, detail, edit, create and delete) to the following apps:

• Extract data import as a separate view, not using the admin #343
• Add views to the formatting app #366
• Add views to the sensor app #367
• Add views to the variable app #368
• Add views to the station app #369

The measurement app does not need views as they have their own dash apps to be managed and, in exceptional circumstances, via de Admin by admin who know what they are doing.