Use Continuation Marker instead of start rank

[steilerDev]

Describe the ultimate goal you want to achieve

Currently the tool is build on the expectation of receiving a maximum of 198 assets per request and builds queries that modify the start rank.

This could be a problem, if the limit changes at any point and already leads to issues with a lot of albums (#294).

How do you think the feature should be implemented

iCloud offers a continuationMarker, which apparently returns remaining results (if there are any): https://developer.apple.com/library/archive/documentation/DataManagement/Conceptual/CloudKitWebServicesReference/QueryingRecords.html#//apple_ref/doc/uid/TP40015240-CH5-SW4