Exercise stubs for missing exercises

[DWalz]

Create Exercis Stubs as mentioned in #2133

Add Exercise Stubs for all exercises mentioned in this comment except for allergies (#2303) and pig-latin (#2315) which are still pending.

I have used final for every function parameter. Function parameters are not final
All classes are package-private.

[SleeplessByte]

@DWalz 3 exercises are failing. Knapsack, Hangman, and Rest-Api.

Can you check if this is "you" or something else? If it's something else we can merge this and fix it separately.

[sanderploegsma]

@DWalz 3 exercises are failing. Knapsack, Hangman, and Rest-Api.

Can you check if this is "you" or something else? If it's something else we can merge this and fix it separately.

I looked into the failures and two of them were caused by a Gradle configuration issue that had nothing to do with the individual exercise configs. I pushed a fix for that, because it's just made visible by the changes in this PR even though this issue was already present in main.

The Knapsack exercise still doesn't compile because it references a class Item that is not present in the stub. @DWalz if you could address this we can get this merged.

[DWalz]

The Item class was indeed missing. I added it with the same implementation from the solution. I assume this class doesn't have to be implemented by the solver themselves.

[sanderploegsma]

Nice work! I found two more small things to take care of though.

[DWalz]

Done. I even remember reading through that in the contributor guide... 😅

[sanderploegsma]

LGTM! @SleeplessByte do you want to have a final look?

[sanderploegsma]

I’m guessing that’s a no 😉