Bulk should be able to define dependance on other bulks

Description

If data depends on each other it should be possible to make a bulk depending on the update of another bulk before publishing of the data inside of it.

Explanation

A bulk dependency would mean, that it is only published if another bulk wants to close as well. Only so could be ensured that data is consistent all the time.

See https://gitlab.tubit.tu-berlin.de/stapps/backend/issues/90 for further information.

cc: @krlwlfrt