Add different ordering/grouping options for the standard results list

[Querela]

Standard ordering of results is by aggregator scan order and their response (time) of the endpoints (TODO: need to verify; changes due to resource selection?).
So this is deterministic, as the ordering does not change but it is not clear to the user. Especially since the ordering of resources is determined at the start of the query and results will then be filled in, so later results can pop in above and/or below existing results.

Possible choices:

• aggregate (group together) by endpoint / institute (if there are multiple endpoints with same institute name)
• order by fastest response time (caveat: for multiple resources per endpoint, some are queried delayed to not overwhelm an endpoint, so they can respond fast but might only be queries when other endpoints already responded, so this counts against endpoints with many resources)
• for ADV, group by available layers?

Note: there already is a button to hide/show endpoints that only respond with errors/diagnostics