Improve the usability of the configuration UI's class browser

[mariusoe]

Currently, users can use the class browser provided by the configuration UI in order to browse existing classes and methods of an agent's application. However, in some cases the usability of the Class Browser is not so good and can be improved. For example, one can lose the overview if classes have a lot of methods. Furthermore, the name of methods is clipped if their signature is very long. In this case, there is no easy way to display the entire name of the method (except waiting for the tooltip).

In this ticket, it is intended to examine and implement how the usability of the Class Browser can be improved.