Optimize /camps endpoint

[manuelmeister]

I think it would be sensible to include whether a camp last period lays in the future or not. We do not display any real data from the periods on the camps view. Also in the future I think it would make sense to load past camps the gui only if explicitly requested by the user (e.g. opening past camps expansion panel)

Originally posted by @manuelmeister in https://github.com/ecamp/ecamp3/pull/3158#discussion_r1020746210

[carlobeltrame]

One wish from PBS DV 2022 mentions some period data which we should probably display:

Super währe wenn auch das Datum vom Lager ersichtlich währe. So kann ich im Jahr 2030 das Lager vom 2022 auswählen und muss nicht wissen welches Motto wir damals hatten.

I.e. the date(s) of each camp should probably be displayed in the camp list. Nevertheless, fetching past camps only on demand could make sense. Although I'm not really sure how much we save in doing that.

[BacLuc]

Related to

• https://github.com/ecamp/ecamp3/issues/4978