calculate_average_Freyrr

[Freyrr]

Check List:

• You have run ./mvnw verify and the project builds successfully
• Tests pass (./test.sh <username> shows no differences between expected and actual outputs)
• All formatting changes by the build are committed
• Your launch script is named calculate_average_<username>.sh (make sure to match casing of your GH user name) and is executable
• Output matches that of calculate_average_baseline.sh
• For new entries, or after substantial changes: When implementing custom hash structures, please point to where you deal with hash collisions (line number)

• Execution time:
• Execution time of reference implementation:

[gunnarmorling]

Please run mvn verify and amend this PR with any changes by the formatter.

[gunnarmorling]

Going to close this one, as I haven't heard back within two days and we're after the cut-off time now. Thx a lot for your efforts nevertheless.