Automatic fitting after loading is implemented badly

[hlxid]

Currently this is the implementation to automatically fit the diagram to the viewport after loading:
https://github.com/PalladioSimulator/Palladio-Supporting-DataFlowConfidentiality-WebBasedEditor/blob/fe45500c80d12c79c1259dc0a0d10cb3f353d6c0/src/commands/load.ts#L150-L166

This is done using a hacky setTimeout. This should be replaced with a solution that guarantees to work every time and not on timing.