TestApp: Add SuggestionSearch for Specifications

[wba2hi]

Blocked by #4

Is your feature request related to a problem? Please describe.
The Specification is quite complex and therefore the list of Specifications to select is huge, making navigation / selection of the correct element really hard. The user should have a more easy way to find the correct Specification he needs.

Describe the solution you'd like
To make navigation more easily, the user should be able to somehow search the existing entries. e.g. instead of having a Spinner, showing the selected entry there should be a TextView, where text can be entered. After entering Text the number of Specifications are automatically reduced to fitting results.

The best search algorithm to use appropriate elements needs to be found / evaluated (e.g. startsWith / contains / ....)