Update handleiding for klant systeem config #8540

Job	Run time
End-to-end tests, chromium	4m 6s
End-to-end tests, firefox	4m 41s
Build and check documentation	1m 54s
End-to-end tests, webkit	4m 29s
Check that documentation for configuration steps is up-to-date	0s
End-to-end tests, msedge	4m 55s
Run the Django test suite (main)	20m 52s
Run the Django test suite (elastic)	4m 46s
Run the Django test suite (openklant)	2m 44s
Run the Django test suite (sequential)	3m 37s
Build (and push) Docker image	1m 59s
Upload coverage information to codecov	14s
	54m 17s

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