backup and ls commands do not retrieve all Tickets, API limits data to 42 entities

[KarstenSchulz]

As we can read in the API docs:

All resources that return collection of entities limit the number of returned entities, by default. If you do not explicitly specify the number of entities to return with the $top query parameter, the server returns maximum 42 first entities. To get the whole collection, you need to use pagination.

We have to re-implement the get requests to download all tickets for the backup command. Maybe we should implement command options like --from and --to to make the count of downloaded tickets configurable.