Remove application stats

[bjrne]

Remove fields like accepted_applications_count and all corresponding logic because we shouldn't save information like that

[aloeser]

I think accepted_applications_count is computed on the fly in https://github.com/hpi-schuelerklub/workshop-portal/blob/e3e5cb113ae91fe6e27d943b8e97141f3326b338/app/models/user.rb#L137 rather than being stored somewhere.
If I recall correctly, this feature was a requirement of our PO. In case it shall be removed anyway, can you explain "information like that"? I'm not really sure what is meant by that :)

[bjrne]

At least the other flag, rejected_applications_count. I'm not sure wether more statistics exist, but if so, I'd rather remove them in order to be compliant with any data/privacy requirements.

[aloeser]

I think rejected_applications_count is computed on the fly too, similar to accepted_applications_count:
https://github.com/hpi-schuelerklub/workshop-portal/blob/e3e5cb113ae91fe6e27d943b8e97141f3326b338/app/models/user.rb#L146

So the statistics are only considered evil when they are somewhere stored and not computed on the fly?

[bjrne]

Good question. I doubt that this will be helpful one day, so I'd rather remove all unnecessary code we have. At least the rejected count will never have usable information since we will always delete these fast.