Performance regression 19 vs. 20

[SystemKeeper]

• Follow-up to Performance regression in after 20.1.0 #4073

Doing the same test as mentioned in the issue above but with #4075 applied sees a halving in the query count (as expected).

Then I downgraded versions and compared 19.1.5 to 21.1.1.:
Query count on 21.1.1 (with patch): ~600 queries (so basically 1 per groupfolder)
Query count on 19.1.5: ~50 queries.

Bisect shows:

2637d7db95e854a942579d3f2914894e8f05951b is the first bad commit
commit 2637d7db95e854a942579d3f2914894e8f05951b
Author: Robin Appelman <robin@icewind.nl>
Date:   Thu Jun 19 16:59:09 2025 +0200

    fix: remove assumptions that all groupfolders share a storage id
    
    Signed-off-by: Robin Appelman <robin@icewind.nl>

[provokateurin]

Also another thing, not sure if related to the new version: #4143