Add the ability to search/filter ATRs in the Active and History Screens

[holtzmak]

We can search/filter on the records held in the respective ViewModels, then notifyListeners to have changes shown on the screens.

• [x] Consider using a combo box or drop down option with the search field so we can search ATRs by different fields, like date delivered, company delivered to, animals in transport
• [x] We don't need a huge selection right now, but addresses would be a good one to have for sure because admins may need to find all transporters who visited such-and-such location for disease tracing purposes.
• [x] Have a button or way to clear the filtered selection and return it to the normal state

[holtzmak]

Actually, ignore the above plan. We can simply translate ATRs to strings and then search those string. This is super scaleable!