Protect against large queries

[stephan271]

Issue Name

ProtectAgainstLargeQueries

Summary

Requests for excessive amount of data from the client via the API should be prevented, since this may lead to crashes in the API server. One solution would be to implement a server side default "limit" variable, in particular for dataset or block queries. However this would require, that the client checks if this limit has been reached. In such cases further calls must be issued by the client with the corresponding skip parameters. In this sense this would be breaking change in the API