Added frontend/configtool related unit testing and refactoring improvements

This pull requests aims to address the outstanding TODOs inside of the frontend configtool related classes

Related #484 
Yes. I realized this shortly after refactoring it. I am thinking of a test that will cover the dropdown menu implementations. However, what I have come up with so far seems a little rigid. For instance, checking that 'English' and 'Deutsch' are inside the language ComboBox could be a test (but if we remove those values a dev would have to update the test.)

However, the checkbox tests (I think) are using hard coded values for checks. Perhaps it is fine to do this here since the entries in the drop down menus do not change as much?