Allow additional test pack selection from UI

[duncangreene]

What is the problem your feature is trying to solve?
In the future it may be useful to have additional test packs to the default 'Device Qualification' and 'Pilot Assessment'. (Some crudely named examples purely for illustration below).

Describe the solution you think would solve the problem
Additional test packs, if present, are not available for selection via the UI currently. These additional test packs, when present, should appear and be selectable from the Devices view.

Testrun 2.0

[duncangreene]

The current workaround is to manually modify the value of the test_pack key within the desired device_config.json. The value should match that of the name key in the corresponding additional test pack .json file.