Add Logging

The current approach to exceptions and errors in the GUI is to either print the stack trace to the terminal or ignore them in the `catch` statements. The appropriate thing to do would be to log these errors.

## Suggested Approach
Use the [`java.util.logging`](https://docs.oracle.com/javase/7/docs/api/java/util/logging/package-summary.html), go through all `catch` bodies, and add relevant information to the log. Beware that some of the exceptions are thrown at times where they might just be handled with a call to `showToast()`.

I would propose using a file for logging, as it seems to be the standard approach, but the name of the file and its location should be considered and tested across all platforms through the generated distributions.

> :information_source: I have marked this issue with https://github.com/Ecdar/Ecdar-GUI/labels/good%20first%20issue, not because it will be very isolated. However, what the appropriate information would be for each log entry should be thoroughly considered