[#2764] Resolve cases concurrently when loading the case list #7708

Job	Run time
Build and check documentation	1m 25s
End-to-end tests, chromium	4m 0s
End-to-end tests, firefox	4m 24s
End-to-end tests, webkit	4m 4s
Check that documentation for configuration steps is up-to-date	1m 14s
Run the Django test suite (main)	20m 45s
End-to-end tests, msedge	4m 12s
Run the Django test suite (elastic)	5m 1s
Run the Django test suite (openklant)	2m 24s
Upload coverage information to codecov	16s
Build (and push) Docker image	1m 44s
	49m 29s

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