Efficient lookups by stratifier/stratum

[timakro]

The BBMRI Sample Locator is unresponsive when results are coming in due to how stratifier and stratum are looked up in getAggregatedPopulationForStratumCode. This should be made more efficient with hash maps.

[timakro]

I had a discussion with @enola-dkfz and she suggested to transition to this format https://github.com/samply/prism/blob/main/resources/test/criteria_groups_bbmri.json for responses. If we were to implement that format we would get O(1) lookups by stratifier and stratum for free. @patrickskowronekdkfz also voiced interest moving away from the blaze response format to something simpler and independent from blaze.

[enola-dkfz]

Also, you might want Lens to get results in the same format regardless of the type of the store (especially when querying different types of stores at the same time, in order to not get many formats and have to add their differently formatted strata up).

If you decide on handling the Prism format I will extract the converter from MeasureReport to a separate Rust library to use in Focus as well.

Tagging @TKussel for a second (third, fourth) opinion.