Show ids for measured quantities

closes #142

This MR introduces that we show also the ids of the measured quantities.

For the main entities (devices, platforms, configurations, sites) it is more or less simple to get the ids of the entries using the frontend alone.

For the measured quantities this is (so far) not the case. The only option is to have edit permissions & click to edit one of the entries.

In order to resolve this problem, this MR introduces the display of the ids in the list view.