Add result aggregation for query templates

[nck-mlcnv]

The new default behaviour is, that each result from the instances of a query template will be counted as the result of the query template. This is done by forcing the query instances to use the id of the query template in the results.
The query templates are considered as queries as well, but they won't be executed.

The ids of those queries that won't be presented in the results (instance queries if individualResults is turned on, query templates otherwise) will be shifted to the right, outside of the range of the number of queries whose results will be presented.

The serialization of the query instaces needed to be changed as well, so that the query instances can be mapped back to their
templates.

The query handler also needs to differentiate between the number of executable queries and the number of queries, that
will be presented in the results, otherwise, too few queries might be executed.

Todo:

• Tests
• Documentation

[nck-mlcnv]

Also, the result model probably needs to be changed, so that it includes the relation between query templates and their instances.