Nested, rollup queries

Kindly add an option to query results of other queries or create a sub-query in the last part of the query.

For example, looking for all objects in object type A that have a tag in a specific tag collection. The latter part of this is related to this other ticket: https://feedback.capacities.io/b/1v35e680/feature-ideas/filter-for-collection

But the second part could very well be results of any other query on a different object type. Filter objects in object type A based on the presence of filters in object B.

On the queries doc (https://docs.capacities.io/reference/queries) there was something on rollup queries, but I haven't seen any ticket linked to that.

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Though a sidenote: the original tag-specific issue could also be solved if one could select a tag collection rather than individual ones only. (collections being added as an option one can filter by)